diff --git a/src/pygui/ISC/AboutDialog.qml b/src/pygui/ISC/AboutDialog.qml
index 3bf7058..386efab 100644
--- a/src/pygui/ISC/AboutDialog.qml
+++ b/src/pygui/ISC/AboutDialog.qml
@@ -111,6 +111,7 @@ Popup {
                     Label { text: "Mfg Date"; font.pixelSize: Theme.fontSm; font.bold: true; color: Theme.subheadingColor; Layout.preferredWidth: 120 }
                     Label { text: "Level"; font.pixelSize: Theme.fontSm; font.bold: true; color: Theme.subheadingColor; Layout.preferredWidth: 80 }
                     Label { text: "License Date"; font.pixelSize: Theme.fontSm; font.bold: true; color: Theme.subheadingColor; Layout.fillWidth: true }
+                    Item { Layout.preferredWidth: 28 }
                 }
 
                 Rectangle {
@@ -132,6 +133,14 @@ Popup {
                         Label { text: modelData.mfgDate; font.pixelSize: Theme.fontMd; color: Theme.bodyColor; Layout.preferredWidth: 120 }
                         Label { text: modelData.level; font.pixelSize: Theme.fontMd; color: Theme.bodyColor; Layout.preferredWidth: 80 }
                         Label { text: modelData.licDate; font.pixelSize: Theme.fontMd; color: Theme.bodyColor; Layout.fillWidth: true }
+                        ToolButton {
+                            Layout.preferredWidth: 28
+                            text: "✕"
+                            font.pixelSize: Theme.fontSm
+                            ToolTip.visible: hovered
+                            ToolTip.text: "Remove license"
+                            onClicked: licenseModel.removeLicense(modelData.serial, modelData.level)
+                        }
                     }
                 }
 
diff --git a/src/pygui/ISC/FirstLaunchWizard.qml b/src/pygui/ISC/FirstLaunchWizard.qml
new file mode 100644
index 0000000..2b43083
--- /dev/null
+++ b/src/pygui/ISC/FirstLaunchWizard.qml
@@ -0,0 +1,148 @@
+import QtQuick
+import QtQuick.Controls
+import QtQuick.Dialogs
+import QtQuick.Layouts
+import ISC
+
+// ===== First-Launch Wizard =====
+// Shown once, on first launch (no settings.json yet). Two skippable steps:
+// load a license, then pick a save folder. Either step can be skipped —
+// review-mode features work without a license, and save dir already has a
+// sensible default, so this is guidance, not a gate.
+Popup {
+    id: root
+    modal: true
+    dim: true
+    closePolicy: Popup.NoAutoClose
+    width: 520
+    height: 320
+    anchors.centerIn: Overlay.overlay
+
+    property int step: 0
+
+    signal finished()
+
+    background: Rectangle {
+        radius: Theme.radiusMd
+        color: Theme.cardBackground
+        border.color: Theme.cardBorder
+        border.width: 1
+    }
+
+    FileDialog {
+        id: licenseFileDialog
+        title: "Load License"
+        nameFilters: ["License files (*.bin)"]
+        onAccepted: {
+            licenseModel.loadLicenseFile(selectedFile.toString())
+            root.step = 1
+        }
+    }
+
+    FolderDialog {
+        id: saveDirDialog
+        title: "Choose a folder to save data"
+        onAccepted: {
+            var dir = decodeURIComponent(String(selectedFolder).replace(/^file:\/\//, ""))
+            deviceController.setSaveDataDir(dir)
+            file_browser.setCurrentDirectory(dir)
+            root.finished()
+        }
+    }
+
+    ColumnLayout {
+        anchors.fill: parent
+        anchors.margins: 28
+        spacing: 20
+
+        Label {
+            text: "Welcome to ISenseCloud"
+            font.pixelSize: Theme.font2xl
+            font.bold: true
+            color: Theme.headingColor
+        }
+
+        // ── Step 1: License ──
+        ColumnLayout {
+            visible: root.step === 0
+            Layout.fillWidth: true
+            Layout.fillHeight: true
+            spacing: 12
+
+            Label {
+                text: "Load your wafer license to enable live device actions\n(Detect, Read, Erase, Debug). You can also do this later\nfrom About."
+                font.pixelSize: Theme.fontMd
+                color: Theme.bodyColor
+                Layout.fillWidth: true
+                wrapMode: Text.WordWrap
+            }
+            Item { Layout.fillHeight: true }
+        }
+
+        // ── Step 2: Save Directory ──
+        ColumnLayout {
+            visible: root.step === 1
+            Layout.fillWidth: true
+            Layout.fillHeight: true
+            spacing: 12
+
+            Label {
+                text: "Choose where wafer read data gets saved. If you skip\nthis, it defaults to a \"csv\" folder inside your app data\ndirectory — changeable anytime from Status."
+                font.pixelSize: Theme.fontMd
+                color: Theme.bodyColor
+                Layout.fillWidth: true
+                wrapMode: Text.WordWrap
+            }
+            Item { Layout.fillHeight: true }
+        }
+
+        // ── Buttons ──
+        RowLayout {
+            Layout.fillWidth: true
+            spacing: 12
+
+            Button {
+                text: "Skip"
+                Layout.preferredWidth: 100
+                Layout.preferredHeight: 36
+                onClicked: root.step === 0 ? (root.step = 1) : root.finished()
+
+                background: Rectangle {
+                    radius: Theme.radiusSm
+                    color: parent.hovered ? Theme.buttonNeutralHover : Theme.buttonNeutralBackground
+                    border.color: Theme.fieldBorder
+                    border.width: 1
+                }
+                contentItem: Label {
+                    text: parent.text
+                    color: Theme.buttonNeutralText
+                    font.pixelSize: Theme.fontMd
+                    horizontalAlignment: Text.AlignHCenter
+                    verticalAlignment: Text.AlignVCenter
+                }
+            }
+
+            Item { Layout.fillWidth: true }
+
+            Button {
+                text: root.step === 0 ? "Load License" : "Choose Folder"
+                Layout.preferredWidth: 160
+                Layout.preferredHeight: 36
+                onClicked: root.step === 0 ? licenseFileDialog.open() : saveDirDialog.open()
+
+                background: Rectangle {
+                    radius: Theme.radiusSm
+                    color: Theme.primaryAccent
+                }
+                contentItem: Label {
+                    text: parent.text
+                    color: "#FFFFFF"
+                    font.pixelSize: Theme.fontMd
+                    font.bold: true
+                    horizontalAlignment: Text.AlignHCenter
+                    verticalAlignment: Text.AlignVCenter
+                }
+            }
+        }
+    }
+}
diff --git a/src/pygui/ISC/HomePage.qml b/src/pygui/ISC/HomePage.qml
index f376e5e..302b877 100644
--- a/src/pygui/ISC/HomePage.qml
+++ b/src/pygui/ISC/HomePage.qml
@@ -19,20 +19,70 @@ Rectangle {
 
     // ===== View State =====
     property int selectedTabIndex: 0
+
+    // Map, Graph, and Data each keep their OWN remembered file selection —
+    // switching tabs must not bleed one tab's pick into another. streamController
+    // itself only holds ONE loaded file at a time (it's a single review session),
+    // so "per-tab selection" means: remember the filename per tab here, and
+    // re-load the right one into that single session whenever the tab becomes
+    // active again. Data tab's compareFileA/B are tracked the same way further
+    // below (Connections on dataTabLoader.item).
+    property string mapReviewFile: ""
+    property string graphReviewFile: ""
+    property string dataCompareFileA: ""
+    property string dataCompareFileB: ""
+
     onSelectedTabIndexChanged: {
         if (selectedTabIndex === 2) {
             file_browser.refreshFiles();
-            streamController.unloadFile()
-        } else if (streamController.mode === "live") {
-            // Leaving the map tab mid-stream: stop and blank the live map.
-            streamController.setMode("review")
+            if (root.mapReviewFile !== "") {
+                if (streamController.loadedFile !== root.mapReviewFile)
+                    streamController.loadFile(root.mapReviewFile)
+            } else if (streamController.loadedFile !== "") {
+                // Map has no memory of its own yet — don't inherit whatever
+                // another tab (e.g. Data's last Run A/B pick) left loaded.
+                streamController.unloadFile()
+            }
+        } else if (selectedTabIndex === 3) {
+            if (root.graphReviewFile !== "") {
+                if (streamController.loadedFile !== root.graphReviewFile)
+                    streamController.loadFile(root.graphReviewFile)
+            } else if (streamController.loadedFile !== "") {
+                streamController.unloadFile()
+            }
         }
+        // Leaving Map tab no longer force-stops a live stream: streamController
+        // (StreamReader + timers) is parented to itself, not to this QML tree,
+        // so acquisition keeps running in the background. The Map Loader just
+        // deactivates — trendChart's local 60s buffer resets on return (it's
+        // QML-item-local state), but the wafer map and stream resume live.
+    }
+
+    // Records which tab's memory a file pick belongs to. Only fires for
+    // picks made while actually on Map(2) or Graph(3) — Data tab's own
+    // Connections (further below) captures its own picks independently,
+    // and this is silent while on Status(0)/Data(1) for any other load.
+    Connections {
+        target: streamController
+        function onLoadedFileChanged() {
+            if (root.selectedTabIndex === 2) root.mapReviewFile = streamController.loadedFile
+            else if (root.selectedTabIndex === 3) root.graphReviewFile = streamController.loadedFile
+        }
+    }
+
+    // Data tab's Run A/B picks survive it being destroyed/recreated by its
+    // Loader (see dataTabLoader below) by mirroring them here.
+    Connections {
+        target: dataTabLoader.item
+        function onCompareFileAChanged() { root.dataCompareFileA = dataTabLoader.item.compareFileA }
+        function onCompareFileBChanged() { root.dataCompareFileB = dataTabLoader.item.compareFileB }
     }
 
 
 
     property bool memoryRead: false
     property bool waferDetected: false
+    property bool waferLicensed: false
 
     Connections {
         target: deviceController
@@ -41,16 +91,41 @@ Rectangle {
             // as an opaque wrapper whose fields read as undefined, so only
             // test truthiness (None on failure, dict on success).
             root.waferDetected = !!result
+            root.waferLicensed = root.waferDetected && deviceController.waferLicensed()
+            // Wafer's own onboard runtime — not a local file a technician can
+            // reset — is what starts the review trial clock. startReplayTrial()
+            // is a true no-op once the marker exists (see license_model.py),
+            // so re-detecting the same over-limit wafer never extends it.
+            if (root.waferDetected && deviceController.waferRuntimeExceeded()) {
+                licenseModel.startReplayTrial()
+            }
         }
         function onParsedDataReady(result) {
             if (result.success && result.csv_path) {
                 streamController.loadFile(result.csv_path)
-                if (root.selectedTabIndex === 0) {
+                // Fires while still on Status(0), before the tab switch below —
+                // the generic per-tab tracker only attributes picks made while
+                // already on Map/Graph, so record this one explicitly.
+                root.mapReviewFile = result.csv_path
+                if (root.selectedTabIndex === 0 && licenseModel.licenses.length > 0) {
                 root.selectedTabIndex = 2
                 }
             }
         }
     }
+    Connections {
+        target: licenseModel
+        function onLicensesChanged() {
+            // Map tab is license-gated: if its licenses vanish while it's
+            // selected, snap back to STATUS instead of showing a bright
+            // pill over an unloaded tab. Also re-check the wafer license
+            // live so Read/Erase don't stay stale until the next detect.
+            if (root.selectedTabIndex === 2 && licenseModel.licenses.length === 0) {
+                root.selectedTabIndex = 0
+            }
+            root.waferLicensed = root.waferDetected && deviceController.waferLicensed()
+        }
+    }
     Connections {
         target: deviceController
         function onReadResult(result) {
@@ -181,6 +256,26 @@ Rectangle {
         id: aboutDialog
     }
 
+    // ===== First-Launch Wizard =====
+    FirstLaunchWizard {
+        id: firstLaunchWizard
+        onFinished: {
+            close()
+            // Wizard closed with no license loaded (skipped, or Load License
+            // never landed a valid file) — start the 30-day review trial now
+            // rather than waiting for a wafer to be detected over-runtime.
+            if (licenseModel.licenses.length === 0) {
+                licenseModel.startReplayTrial()
+            }
+            settingsModel.saveSettings()
+        }
+    }
+    Component.onCompleted: {
+        if (isFirstLaunch) {
+            firstLaunchWizard.open()
+        }
+    }
+
     // ===== Main Layout: Rail + Workspace =====
     RowLayout {
         anchors.fill: parent
@@ -246,6 +341,11 @@ Rectangle {
                             delegate: Button {
                                 id: pillBtn
                                 checked: root.selectedTabIndex === index
+                                // MAP (index 2) is locked until a valid license .bin is installed.
+                                // Stays enabled (not `enabled: false`) so hover still fires and the
+                                // tooltip can explain why — a disabled Item receives no mouse/hover
+                                // events at all, which would silently kill the tooltip below.
+                                property bool locked: index === 2 && licenseModel.licenses.length === 0
                                 flat: true
                                 Layout.fillWidth: true
                                 Layout.fillHeight: true
@@ -276,7 +376,7 @@ Rectangle {
                                         source: model.icon
                                         sourceSize.width: 16; sourceSize.height: 16
                                         color: (pillBtn.checked || pillBtn.hovered) ? Theme.headingColor : Theme.sideMutedText
-                                        opacity: pillBtn.checked ? 0.9 : pillBtn.hovered ? 0.85 : 0.4
+                                        opacity: !pillBtn.locked ? (pillBtn.checked ? 0.9 : pillBtn.hovered ? 0.85 : 0.4) : 0.2
                                         Behavior on color {
                                             ColorAnimation { duration: Theme.durationFast }
                                         }
@@ -295,7 +395,7 @@ Rectangle {
                                         font.pixelSize: Theme.fontSm
                                         font.bold: true
                                         font.letterSpacing: 1.0
-                                        opacity: pillBtn.checked ? 1.0 : 0.0
+                                        opacity: !pillBtn.locked ? (pillBtn.checked ? 1.0 : 0.0) : 0.25
                                         clip: true
                                         Behavior on width {
                                             NumberAnimation { duration: 200; easing.type: Easing.OutCubic }
@@ -311,10 +411,12 @@ Rectangle {
 
                                 AppToolTip {
                                     visible: pillBtn.hovered
-                                    text: "<b>" + model.label + "</b>: " + model.desc
+                                    text: (index === 2 && licenseModel.licenses.length === 0)
+                                        ? "<b>MAP</b>: No license loaded — load one in About to unlock"
+                                        : "<b>" + model.label + "</b>: " + model.desc
                                 }
 
-                                onClicked: root.selectedTabIndex = index
+                                onClicked: if (!pillBtn.locked) root.selectedTabIndex = index
                             }
                         }
                     }
@@ -594,6 +696,8 @@ Rectangle {
                         SourcePanel {
                             anchors.fill: parent
                             anchors.margins: 14
+                            selectedTabIndex: root.selectedTabIndex
+                            dataTab: dataTabLoader.item
                         }
                     }
                 }
@@ -632,10 +736,24 @@ Rectangle {
                     id: dataTabLoader
                     source: "Tabs/DataTab.qml"
                     active: StackLayout.index === root.selectedTabIndex
+                    // Component is still recreated lazily on every tab switch
+                    // (memory-cheap, matches Status/Map/Graph) — what survives
+                    // is just the two filenames (root.dataCompareFileA/B),
+                    // restored here so Run A/B picks and their two-color
+                    // highlight aren't lost on return. Computed DTW results
+                    // are NOT re-run automatically — re-fetching is a real
+                    // (if fast) backend call, so the user re-clicks "Run DTW
+                    // Comparison" rather than it silently firing on tab entry.
+                    onLoaded: {
+                        item.compareFileA = root.dataCompareFileA
+                        item.compareFileB = root.dataCompareFileB
+                        item.activeBox = root.dataCompareFileB !== "" ? 0
+                            : root.dataCompareFileA !== "" ? 2 : 1
+                    }
                 }
                 Loader {
                     source: "Tabs/WaferMapTab.qml"
-                    active: StackLayout.index === root.selectedTabIndex
+                    active: StackLayout.index === root.selectedTabIndex && licenseModel.licenses.length > 0
                 }
                 Loader {
                     source: "Tabs/GraphTab.qml"
diff --git a/src/pygui/ISC/Tabs/components/RailActionButton.qml b/src/pygui/ISC/Tabs/components/RailActionButton.qml
index 47a1207..71d66ce 100644
--- a/src/pygui/ISC/Tabs/components/RailActionButton.qml
+++ b/src/pygui/ISC/Tabs/components/RailActionButton.qml
@@ -15,6 +15,9 @@ Rectangle {
     // Set true to show the button as "active" (e.g. a one-shot toggle
     // that's mid-operation), independent of hover/press state.
     property bool toggled: false
+    // Shown on hover even while disabled, e.g. to explain *why* a greyed-out
+    // action is unavailable. Empty string shows no tooltip.
+    property string tooltipText: ""
     property color _textColor: !root.enabled ? Theme.sideMutedText
         : root.destructive ? Theme.statusErrorColor
         : Theme.headingColor
@@ -23,7 +26,7 @@ Rectangle {
 
     implicitHeight: Theme.sideButtonHeight
     radius: 8
-    color: root.toggled || mouseArea.containsMouse || mouseArea.pressed
+    color: root.toggled || (root.enabled && (mouseArea.containsMouse || mouseArea.pressed))
         ? Theme.sideActiveBackground : "transparent"
     border.width: 0
 
@@ -64,10 +67,17 @@ Rectangle {
     MouseArea {
         id: mouseArea
         anchors.fill: parent
-        hoverEnabled: root.enabled
+        // Hover stays live while disabled so tooltipText can explain why —
+        // click is still gated on root.enabled below.
+        hoverEnabled: true
         cursorShape: root.enabled ? Qt.PointingHandCursor : Qt.ArrowCursor
         onClicked: {
             if (root.enabled) root.clicked()
         }
     }
+
+    AppToolTip {
+        visible: root.tooltipText.length > 0 && mouseArea.containsMouse
+        text: root.tooltipText
+    }
 }
diff --git a/src/pygui/ISC/Tabs/components/SourcePanel.qml b/src/pygui/ISC/Tabs/components/SourcePanel.qml
index 5df2bac..a76116b 100644
--- a/src/pygui/ISC/Tabs/components/SourcePanel.qml
+++ b/src/pygui/ISC/Tabs/components/SourcePanel.qml
@@ -13,6 +13,11 @@ ColumnLayout {
     property string exportSummary: ""
     property string importSummary: ""
 
+    // Set by HomePage.qml — a separate .qml file has its own id scope, so
+    // dataTabLoader/root from HomePage aren't reachable here directly.
+    property int selectedTabIndex: 0
+    property var dataTab: null
+
     Connections {
         target: batchExportController
         function onExportFinished(summary) {
@@ -352,11 +357,7 @@ ColumnLayout {
                 return (modelData.baseName + modelData.waferType + modelData.date).toLowerCase().indexOf(q) >= 0;
             }
 
-            readonly property var dataTab: {
-                try {
-                    return (root.selectedTabIndex === 1 && dataTabLoader.item) ? dataTabLoader.item : null;
-                } catch (e) { return null; }
-            }
+            readonly property var dataTab: root.selectedTabIndex === 1 ? root.dataTab : null
 
             // Run A's effective file: the master file when "Compare vs Master
             // File" is toggled on, otherwise the manually selected file.
diff --git a/src/pygui/ISC/Tabs/components/StatusActionsPanel.qml b/src/pygui/ISC/Tabs/components/StatusActionsPanel.qml
index 746c09c..24ed6b7 100644
--- a/src/pygui/ISC/Tabs/components/StatusActionsPanel.qml
+++ b/src/pygui/ISC/Tabs/components/StatusActionsPanel.qml
@@ -44,7 +44,9 @@ ColumnLayout {
                 label: "READ MEMORY"
                 iconSource: "../icons/read.svg"
                 Layout.fillWidth: true
-                enabled: deviceController.waferDetected && !deviceController.operationInProgress
+                enabled: deviceController.waferDetected && root.waferLicensed && !deviceController.operationInProgress
+                tooltipText: (deviceController.waferDetected && !root.waferLicensed)
+                    ? "Wafer not licensed — load its license .bin (About dialog)" : ""
                 onClicked: deviceController.readMemoryAsync()
             }
 
@@ -53,7 +55,9 @@ ColumnLayout {
                 iconSource: "../icons/erase.svg"
                 Layout.fillWidth: true
                 destructive: true
-                enabled: deviceController.waferDetected && !deviceController.operationInProgress
+                enabled: deviceController.waferDetected && root.waferLicensed && !deviceController.operationInProgress
+                tooltipText: (deviceController.waferDetected && !root.waferLicensed)
+                    ? "Wafer not licensed — load its license .bin (About dialog)" : ""
                 onClicked: deviceController.eraseMemory(
                     deviceController.selectedPort)
             }
@@ -65,7 +69,9 @@ ColumnLayout {
                 // One-shot toggle: "on" while the debug read is in flight,
                 // resets automatically once deviceController flips status.
                 toggled: deviceController.connectionStatus === "Reading debug..."
-                enabled: deviceController.waferDetected && !deviceController.operationInProgress
+                enabled: deviceController.waferDetected && root.waferLicensed && !deviceController.operationInProgress
+                tooltipText: (deviceController.waferDetected && !root.waferLicensed)
+                    ? "Wafer not licensed — load its license .bin (About dialog)" : ""
                 onClicked: deviceController.readDebug(deviceController.selectedPort)
             }
         }
diff --git a/src/pygui/ISC/Tabs/components/StreamControlPanel.qml b/src/pygui/ISC/Tabs/components/StreamControlPanel.qml
index b6cbf2d..8908cfb 100644
--- a/src/pygui/ISC/Tabs/components/StreamControlPanel.qml
+++ b/src/pygui/ISC/Tabs/components/StreamControlPanel.qml
@@ -62,7 +62,22 @@ Rectangle {
 
             TabBar {
                 id: modeBar
+                // Guards the programmatic sync below from re-triggering
+                // onCurrentIndexChanged's setMode()/startStream() side effects.
+                property bool _syncing: false
                 currentIndex: 0
+                Component.onCompleted: {
+                    // WaferMapTab (and this panel) is destroyed/recreated by
+                    // its Loader on every tab switch, so this TabBar always
+                    // starts fresh at index 0 — but streamController.mode is
+                    // backend state that outlives the switch (streaming now
+                    // continues off-tab). Sync the visual index to the real
+                    // mode on creation instead of defaulting to "Review" and
+                    // silently disagreeing with a still-live stream.
+                    _syncing = true
+                    currentIndex = streamController.mode === "live" ? 1 : 0
+                    _syncing = false
+                }
                 spacing: 2
                 padding: 2
                 Layout.fillWidth: true
@@ -152,6 +167,7 @@ Rectangle {
             }
 
             onCurrentIndexChanged: {
+                    if (_syncing) return;
                     if (currentIndex === 1) {
                         if (deviceController.connectionStatus !== "Connected") {
                             currentIndex = 0;
diff --git a/src/pygui/ISC/qmldir b/src/pygui/ISC/qmldir
index b6d2841..258c288 100644
--- a/src/pygui/ISC/qmldir
+++ b/src/pygui/ISC/qmldir
@@ -5,6 +5,7 @@ module ISC
 Main 1.0 Main.qml
 HomePage 1.0 HomePage.qml
 AboutDialog 1.0 AboutDialog.qml
+FirstLaunchWizard 1.0 FirstLaunchWizard.qml
 
 # ===== Singleton Theme =====
 singleton Theme 1.0 Theme.qml
diff --git a/src/pygui/__main__.py b/src/pygui/__main__.py
index 72c5cae..eb4c02f 100644
--- a/src/pygui/__main__.py
+++ b/src/pygui/__main__.py
@@ -49,6 +49,9 @@ def main() -> int:
     # Settings tab is visible to the device layer immediately — no reload,
     # no second copy to go stale.
     data_dir = str(default_data_dir())
+    # settings.json only exists once something has saved — absence means this
+    # machine has never run the app before (first-launch wizard trigger).
+    is_first_launch = not (Path(data_dir) / "settings.json").exists()
     raw_settings = LocalSettings.read_settings(data_dir)
 
     settings_model = LocalSettingsModel(raw_settings, data_dir)
@@ -56,6 +59,7 @@ def main() -> int:
     settings_model.loadSettings()
     engine.rootContext().setContextProperty("settingsModel", settings_model)
     engine.rootContext().setContextProperty("file_browser", select_file_dialog_model)
+    engine.rootContext().setContextProperty("isFirstLaunch", is_first_launch)
 
     # App version from package metadata so the About dialog can't drift
     # from pyproject.toml.
@@ -65,17 +69,19 @@ def main() -> int:
         app_version = "dev"
     engine.rootContext().setContextProperty("appVersion", app_version)
 
+    # ===== License Model (About dialog grid, replay trial) =====
+    license_model = LicenseModel(data_dir)
+    engine.rootContext().setContextProperty("licenseModel", license_model)
+
     # ===== Device Controller (serial comm) =====
-    device_controller = DeviceController(raw_settings, data_dir)
+    device_controller = DeviceController(
+        raw_settings, data_dir, license_lookup=license_model.levelForWafer
+    )
     engine.rootContext().setContextProperty("deviceController", device_controller)
 
     # Source panel browses the same folder recordings/reads are saved to.
     select_file_dialog_model.setCurrentDirectory(str(device_controller.saveDataDir))
 
-    # ===== License Model (About dialog grid, replay trial) =====
-    license_model = LicenseModel(data_dir)
-    engine.rootContext().setContextProperty("licenseModel", license_model)
-
     # ===== Session Controller (live/review wafer dashboard) =====
     stream_controller = SessionController()
     engine.rootContext().setContextProperty("streamController", stream_controller)
diff --git a/src/pygui/backend/controllers/device_controller.py b/src/pygui/backend/controllers/device_controller.py
index 96f65e8..31ce017 100644
--- a/src/pygui/backend/controllers/device_controller.py
+++ b/src/pygui/backend/controllers/device_controller.py
@@ -9,7 +9,7 @@ import sys
 import threading
 from datetime import datetime
 from pathlib import Path
-from typing import Any, Optional
+from typing import Any, Callable, Optional
 
 from PySide6.QtCore import Property, QObject, Qt, Signal, Slot
 
@@ -29,6 +29,12 @@ from pygui.serialcomm.serial_port import WaferInfo
 
 log = logging.getLogger(__name__)
 
+# ponytail: placeholder pending real hardware spec — the C# reference had two
+# runtime numbers (350, 21600s) but neither was ever an enforced comparison,
+# just a dead constant and a display string. Recalibrate once product gives
+# the actual recommended figure.
+WAFER_RUNTIME_WARNING_SECONDS = 350
+
 
 class DeviceController(QObject):
     """Controls serial communication with the temperature-sensing wafer.
@@ -57,10 +63,17 @@ class DeviceController(QObject):
     _eraseFinished = Signal(bool)                # (success)
     _debugFinished = Signal(dict)                # (result_dict)
 
-    def __init__(self, settings: LocalSettings, data_dir: str, parent: QObject | None = None) -> None:
+    def __init__(
+        self,
+        settings: LocalSettings,
+        data_dir: str,
+        license_lookup: Callable[[str], str] = lambda s: "",
+        parent: QObject | None = None,
+    ) -> None:
         super().__init__(parent)
         self._settings = settings
         self._data_dir = data_dir
+        self._license_lookup = license_lookup
         from pygui.serialcomm.device_service import DeviceService
         self._service = DeviceService(settings)
 
@@ -266,6 +279,21 @@ class DeviceController(QObject):
             "series": series_data,
         }
 
+    @Slot(result=bool)
+    def waferLicensed(self) -> bool:
+        """Check if the current wafer has a valid license."""
+        return self._wafer_license_level() != ""
+
+    @Slot(result=bool)
+    def waferRuntimeExceeded(self) -> bool:
+        """True if the detected wafer's onboard runtime is past the recommended limit."""
+        runtime = int(self._last_wafer_info.get("runtime", 0))
+        return runtime > WAFER_RUNTIME_WARNING_SECONDS
+
+    def _wafer_license_level(self) -> str:
+        """Get license level for the current wafer serial number."""
+        return self._license_lookup(self._last_wafer_info.get("serialNumber", ""))
+
     def _append_log(self, message: str) -> None:
         """Append a message to the activity log and emit updated log."""
         ts = datetime.now().strftime("%H:%M:%S")
@@ -383,6 +411,12 @@ class DeviceController(QObject):
                 self._last_wafer_info = wafer_dict
                 self._set_wafer_detected(True)
                 self._set_connection_status("Connected")
+                if self.waferRuntimeExceeded():
+                    self._append_log(
+                        f"Warning: wafer runtime {wafer_dict['runtime']}s exceeds "
+                        f"recommended {WAFER_RUNTIME_WARNING_SECONDS}s — "
+                        "consider ordering a replacement wafer"
+                    )
                 self.detectResult.emit(wafer_dict)
                 self.selectedPortChanged.emit()
                 self._save_status()
@@ -410,6 +444,11 @@ class DeviceController(QObject):
             self._append_log("Already busy — ignoring read request")
             return
 
+        if self._wafer_license_level() == "":
+            self._append_log("Wafer not licensed — load its license .bin (About dialog)")
+            self.readResult.emit({"error": "Wafer not licensed"})
+            return
+
         if not self._selected_port:
             self._append_log("No wafer detected — run Detect Wafer first")
             self.readResult.emit({"error": "No port — detect wafer first"})
@@ -470,6 +509,11 @@ class DeviceController(QObject):
             self._append_log("Already busy — ignoring erase request")
             return
 
+        if self._wafer_license_level() == "":
+            self._append_log("Wafer not licensed — load its license .bin (About dialog)")
+            self.eraseResult.emit({"success": False})
+            return
+
         self._set_operation_progress(True)
         self._set_connection_status("Erasing...")
         self.portsUpdated.emit(self._service.enumerate_ports())
@@ -510,6 +554,13 @@ class DeviceController(QObject):
         if self._operation_in_progress:
             self._append_log("Already busy — ignoring debug read request")
             return
+
+        # Debug read returns D1 sensor data — same license boundary as READ MEMORY.
+        if self._wafer_license_level() == "":
+            self._append_log("Wafer not licensed — load its license .bin (About dialog)")
+            self.debugResult.emit({"success": False, "error": "Wafer not licensed"})
+            return
+
         self._set_operation_progress(True)
         self._set_connection_status("Reading debug...")
         self.portsUpdated.emit(self._service.enumerate_ports())
diff --git a/src/pygui/backend/license/license_model.py b/src/pygui/backend/license/license_model.py
index c2fd12e..e6d6068 100644
--- a/src/pygui/backend/license/license_model.py
+++ b/src/pygui/backend/license/license_model.py
@@ -33,7 +33,10 @@ class LicenseModel(QObject):
 
     Licenses live in ``<data_dir>/licenses`` (mirrors C#'s
     ``DataDir\\licenses``). The 30-day replay trial marker is
-    ``<data_dir>/replay.lic``.
+    ``<data_dir>/replay.lic``. "Removed" licenses are tracked in
+    ``<data_dir>/removed_licenses.txt`` (one ``serial-level`` per line) —
+    removal hides a license from the app without deleting its ``.bin``,
+    so the vendor-issued file always stays recoverable on disk.
     """
 
     licensesChanged = Signal()
@@ -65,8 +68,12 @@ class LicenseModel(QObject):
 
     @Slot()
     def refresh(self) -> None:
-        """Re-scan the licenses directory."""
-        self._licenses = read_license_files(self._licenses_dir)
+        """Re-scan the licenses directory, filtering out removed entries."""
+        removed = self._read_removed()
+        self._licenses = [
+            lic for lic in read_license_files(self._licenses_dir)
+            if f"{lic.serial}-{lic.level}" not in removed
+        ]
         self.licensesChanged.emit()
 
     # ── Load License ──────────────────────────────────────────────────
@@ -92,13 +99,61 @@ class LicenseModel(QObject):
             log.warning("License file failed validation: %s", src.name)
             return False
 
+        # Skip the copy when src already IS the file in place — e.g. re-picking
+        # a previously-removed license from <data_dir>/licenses/ to un-hide it.
+        # shutil.copyfile raises SameFileError (an OSError) on src == dst.
         try:
             self._licenses_dir.mkdir(parents=True, exist_ok=True)
-            shutil.copyfile(src, self._licenses_dir / src.name)
+            dst = self._licenses_dir / src.name
+            if src.resolve() != dst.resolve():
+                shutil.copyfile(src, dst)
         except OSError as exc:
             log.warning("Cannot copy license into %s: %s", self._licenses_dir, exc)
             return False
 
+        # An explicit (re)load un-hides the license if it was previously
+        # removed from the app view — the user is deliberately bringing it back.
+        self._discard_removed(lic.serial, lic.level)
+        self.refresh()
+        return True
+
+    # ── Remove License (app-side only — .bin stays on disk) ────────────
+    @property
+    def _removed_marker(self) -> Path:
+        return self._data_dir / "removed_licenses.txt"
+
+    def _read_removed(self) -> set[str]:
+        try:
+            return set(self._removed_marker.read_text().splitlines())
+        except OSError:
+            return set()
+
+    def _discard_removed(self, serial: str, level: str) -> None:
+        entry = f"{serial}-{level}"
+        removed = self._read_removed()
+        if entry not in removed:
+            return
+        removed.discard(entry)
+        try:
+            self._removed_marker.write_text("\n".join(sorted(removed)) + "\n" if removed else "")
+        except OSError as exc:
+            log.warning("Cannot update removed-license marker %s: %s", self._removed_marker, exc)
+
+    @Slot(str, str, result=bool)
+    def removeLicense(self, serial: str, level: str) -> bool:
+        """Hide license (serial, level) from the app. Leaves the .bin on disk."""
+        if not any(lic.serial == serial and lic.level == level for lic in self._licenses):
+            return False
+
+        entry = f"{serial}-{level}"
+        removed = self._read_removed()
+        removed.add(entry)
+        try:
+            self._removed_marker.write_text("\n".join(sorted(removed)) + "\n")
+        except OSError as exc:
+            log.warning("Cannot update removed-license marker %s: %s", self._removed_marker, exc)
+            return False
+
         self.refresh()
         return True
 
@@ -128,9 +183,17 @@ class LicenseModel(QObject):
 
     @Slot(result=bool)
     def startReplayTrial(self) -> bool:
-        """Create the trial marker (idempotent). False on I/O failure."""
+        """Create the trial marker if absent. False on I/O failure.
+
+        Must never touch an existing marker: Path.touch(exist_ok=True) bumps
+        mtime even when the file is already there, which would silently push
+        the 30-day clock forward every time this is called on an
+        already-started trial — an infinite-reset hole.
+        """
+        if self._trial_marker.exists():
+            return True
         try:
-            self._trial_marker.touch(exist_ok=True)
+            self._trial_marker.touch()
             return True
         except OSError as exc:
             log.warning("Cannot create trial marker: %s", exc)
diff --git a/src/pygui/backend/visualization/wafer_map_item.py b/src/pygui/backend/visualization/wafer_map_item.py
index a44bb61..a1295ff 100644
--- a/src/pygui/backend/visualization/wafer_map_item.py
+++ b/src/pygui/backend/visualization/wafer_map_item.py
@@ -378,12 +378,7 @@ class WaferMapItem(QQuickPaintedItem):
                 return idx
         return -1
 
-    # TODO P6.1: build batch export on top of this single-frame export
-    #   THINKING: export_image() already does the hard part (grabToImage → PNG);
-    #   batch export is just a loop over file_browser.files that loads each CSV
-    #   through the existing wafer-map pipeline and calls this per file into a
-    #   chosen output dir, plus an optional summary CSV of (file, min/max/mean).
-    #   No new rendering code needed — see docs/pending/alpha-release-polish-plan.md §6.1.
+
     @Slot(str, result=bool)
     @Slot(str, str, result=bool)
     def export_image(self, file_path: str, extra: str = "") -> bool:
@@ -520,13 +515,6 @@ class WaferMapItem(QQuickPaintedItem):
         r = max(math.hypot(s.x, s.y) for s in self._sensors)
         return r * 1.05
 
-    # TODO P6.2: reuse this for the edge-to-center delta metric
-    #   THINKING: radial_metrics.py (new) needs the same "which sensors are near
-    #   the edge vs. near the center" bucketing this function already computes
-    #   for ring-line drawing — do NOT re-derive ring boundaries separately, this
-    #   already handles round vs. square wafer shapes correctly (see family_spec.py
-    #   square-wafer work). Outermost group ≈ edge sensors, innermost ≈ center.
-    #   See docs/pending/alpha-release-polish-plan.md §6.2.
     def _sensor_ring_radii_mm(self) -> list[float]:
         """Distinct radial distances of sensor groups, sorted ascending, plus the outer boundary."""
         if not self._sensors:
diff --git a/tests/test_device_controller.py b/tests/test_device_controller.py
index d01b635..08a2239 100644
--- a/tests/test_device_controller.py
+++ b/tests/test_device_controller.py
@@ -50,6 +50,11 @@ def test_detect_wafer_spawns_thread(controller):
         assert controller.operationInProgress
 
 def test_read_memory_without_detect_return_error(controller):
+    # License the wafer so this test exercises the "no port" branch rather
+    # than short-circuiting on the license guard.
+    controller._license_lookup = lambda s: "02"
+    controller._last_wafer_info = {"serialNumber": "A00001"}
+
     emitted_result = None
     def on_read_result(result):
         nonlocal emitted_result
@@ -91,6 +96,9 @@ def test_clear_session(controller):
     assert controller.lastWaferInfo == ["", "", 0, "", 0, 0]
 
 def test_erase_memory_spawns_thread(controller):
+    # License the wafer so the new license guard doesn't block the erase.
+    controller._license_lookup = lambda s: "02"
+    controller._last_wafer_info = {"serialNumber": "A00001"}
     with patch("threading.Thread") as mock_thread:
         controller.eraseMemory("COM1")
         mock_thread.assert_called_once()
@@ -109,11 +117,32 @@ def test_erase_memory_handler(controller):
     assert not controller.operationInProgress
 
 def test_read_debug_spawns_thread(controller):
+    # License the wafer so the license guard doesn't block the debug read.
+    controller._license_lookup = lambda s: "02"
+    controller._last_wafer_info = {"serialNumber": "A00001"}
     with patch("threading.Thread") as mock_thread:
         controller.readDebug("COM1")
         mock_thread.assert_called_once()
         assert controller.operationInProgress
 
+def test_read_debug_denied_without_license(controller):
+    """readDebug() returns D1 sensor data, so it obeys the same license guard."""
+    controller._license_lookup = lambda s: ""
+    controller._last_wafer_info = {"serialNumber": "A00001"}
+
+    emitted_result = None
+    def on_debug_result(result):
+        nonlocal emitted_result
+        emitted_result = result
+    controller.debugResult.connect(on_debug_result)
+
+    with patch("threading.Thread") as mock_thread:
+        controller.readDebug("COM1")
+        mock_thread.assert_not_called()
+
+    assert emitted_result == {"success": False, "error": "Wafer not licensed"}
+    assert not controller.operationInProgress
+
 def test_read_debug_handler(controller):
     emitted_result = None
     def on_debug_result(result):
@@ -300,3 +329,136 @@ def test_export_dir_created_under_save_data_dir(controller):
 
     assert result == str(Path(controller.saveDataDir) / "Export")
     assert Path(result).is_dir()
+
+
+def test_wafer_licensed_default_no_license(controller):
+    """Default license_lookup (empty lambda) -> waferLicensed() is False."""
+    controller._last_wafer_info = {"serialNumber": "P00001"}
+    assert controller.waferLicensed() is False
+
+
+def test_wafer_licensed_with_valid_license(mock_settings):
+    """A license_lookup returning a level -> waferLicensed() is True."""
+    import shutil
+    import tempfile
+
+    temp_dir = tempfile.mkdtemp()
+    try:
+        controller = DeviceController(
+            mock_settings, temp_dir, license_lookup=lambda s: "02"
+        )
+        controller._last_wafer_info = {"serialNumber": "A00001"}
+        assert controller.waferLicensed() is True
+    finally:
+        shutil.rmtree(temp_dir)
+
+
+def test_read_memory_denied_without_license(controller):
+    """readMemoryAsync() must refuse to spawn a thread for an unlicensed wafer."""
+    controller._license_lookup = lambda s: ""
+    controller._last_wafer_info = {"serialNumber": "A00001"}
+    controller._selected_port = "COM1"
+
+    emitted_result = None
+    def on_read_result(result):
+        nonlocal emitted_result
+        emitted_result = result
+    controller.readResult.connect(on_read_result)
+
+    with patch("threading.Thread") as mock_thread:
+        controller.readMemoryAsync()
+        mock_thread.assert_not_called()
+
+    assert emitted_result is not None
+    assert "error" in emitted_result
+    assert not controller.operationInProgress
+
+
+def test_erase_memory_denied_without_license(controller):
+    """eraseMemory() must refuse to spawn a thread for an unlicensed wafer."""
+    controller._license_lookup = lambda s: ""
+    controller._last_wafer_info = {"serialNumber": "A00001"}
+
+    emitted_result = None
+    def on_erase_result(result):
+        nonlocal emitted_result
+        emitted_result = result
+    controller.eraseResult.connect(on_erase_result)
+
+    with patch("threading.Thread") as mock_thread:
+        controller.eraseMemory("COM1")
+        mock_thread.assert_not_called()
+
+    assert emitted_result == {"success": False}
+    assert not controller.operationInProgress
+
+
+def test_read_memory_allowed_with_license(controller):
+    """readMemoryAsync() proceeds and spawns a thread once the wafer is licensed."""
+    controller._license_lookup = lambda s: "02"
+    controller._last_wafer_info = {"serialNumber": "A00001"}
+    controller._selected_port = "COM1"
+
+    with patch("threading.Thread") as mock_thread:
+        controller.readMemoryAsync()
+        mock_thread.assert_called_once()
+        assert controller.operationInProgress
+
+
+def test_erase_memory_allowed_with_license(controller):
+    """eraseMemory() proceeds and spawns a thread once the wafer is licensed."""
+    controller._license_lookup = lambda s: "02"
+    controller._last_wafer_info = {"serialNumber": "A00001"}
+
+    with patch("threading.Thread") as mock_thread:
+        controller.eraseMemory("COM1")
+        mock_thread.assert_called_once()
+        assert controller.operationInProgress
+
+
+def test_wafer_runtime_exceeded_false_under_threshold(controller):
+    controller._last_wafer_info = {"runtime": 100}
+    assert controller.waferRuntimeExceeded() is False
+
+
+def test_wafer_runtime_exceeded_true_over_threshold(controller):
+    controller._last_wafer_info = {"runtime": 999}
+    assert controller.waferRuntimeExceeded() is True
+
+
+def test_detect_finished_warns_on_runtime_exceeded(controller):
+    info = WaferInfo(
+        family_code="P",
+        serial_number="P00001",
+        sensor_count=244,
+        mfg_date_hex="12345678",
+        sensor_assigned_hex="01",
+        locked_hex="00",
+        runtime=999,
+        cycle_count=10,
+    )
+    log_messages = []
+    controller.activityLogUpdated.connect(lambda msg: log_messages.append(msg))
+
+    controller._handle_detect_finished("COM1", info)
+
+    assert any("exceeds recommended" in msg for msg in log_messages)
+
+
+def test_detect_finished_no_warning_under_threshold(controller):
+    info = WaferInfo(
+        family_code="P",
+        serial_number="P00001",
+        sensor_count=244,
+        mfg_date_hex="12345678",
+        sensor_assigned_hex="01",
+        locked_hex="00",
+        runtime=100,
+        cycle_count=10,
+    )
+    log_messages = []
+    controller.activityLogUpdated.connect(lambda msg: log_messages.append(msg))
+
+    controller._handle_detect_finished("COM1", info)
+
+    assert not any("exceeds recommended" in msg for msg in log_messages)
diff --git a/tests/test_device_controller_license.py b/tests/test_device_controller_license.py
deleted file mode 100644
index b94f378..0000000
--- a/tests/test_device_controller_license.py
+++ /dev/null
@@ -1,8 +0,0 @@
-# TODO P4.2: unit tests for the DeviceController license guard (plan §4.2,
-#   docs/pending/license-gating-plan.md). Two cases:
-#   1. license_lookup=lambda s: "" + fake _last_wafer_info → readMemoryAsync()
-#      emits readResult {"error": ...} and spawns no thread.
-#   2. lookup returning "02" → proceeds to _read_worker (mock DeviceService).
-#   THINKING: guard is a trust boundary (plan §2.1); these fail if someone
-#   reorders the busy/license checks or renames the "serialNumber" key.
-#   Depends on P1.2 + P2.1 being implemented.
diff --git a/tests/test_license.py b/tests/test_license.py
index 57673a6..2908cd4 100644
--- a/tests/test_license.py
+++ b/tests/test_license.py
@@ -135,6 +135,63 @@ def test_model_load_license_file_url(tmp_path, qapp):
     assert model.loadLicenseFile("file://" + src) is True
 
 
+def test_model_remove_license_keeps_bin_on_disk(tmp_path, qapp):
+    (tmp_path / "licenses").mkdir()
+    write_license(tmp_path / "licenses", serial="A00001", level="01")
+    model = LicenseModel(str(tmp_path))
+    assert len(model.licenses) == 1
+
+    assert model.removeLicense("A00001", "01") is True
+    assert model.licenses == []
+    # app-side removal only — the vendor-issued .bin is never deleted
+    assert (tmp_path / "licenses" / "A00001-01.bin").exists()
+
+    # sticky across a fresh scan (not just until the next refresh)
+    model.refresh()
+    assert model.licenses == []
+
+    # sticky across a real relaunch — brand new instance, no shared state
+    relaunched = LicenseModel(str(tmp_path))
+    assert relaunched.licenses == []
+
+
+def test_model_remove_license_missing_returns_false(tmp_path, qapp):
+    model = LicenseModel(str(tmp_path))
+    assert model.removeLicense("Z99999", "00") is False
+
+
+def test_model_reload_after_remove_unhides(tmp_path, qapp):
+    src_dir = tmp_path / "dl"
+    src_dir.mkdir()
+    src = write_license(src_dir, serial="A00001", level="01")
+    model = LicenseModel(str(tmp_path / "appdata"))
+    assert model.loadLicenseFile(src) is True
+    assert len(model.licenses) == 1
+
+    model.removeLicense("A00001", "01")
+    assert model.licenses == []
+
+    # explicit reload of the same file brings it back
+    assert model.loadLicenseFile(src) is True
+    assert len(model.licenses) == 1
+
+
+def test_model_reload_in_place_unhides(tmp_path, qapp):
+    """Un-hiding by re-picking the .bin from its own <data_dir>/licenses/ dir —
+    src and dst resolve to the same file, must not error on the copy step."""
+    model = LicenseModel(str(tmp_path / "appdata"))
+    write_license(tmp_path / "appdata" / "licenses", serial="A00001", level="01")
+    model.refresh()
+    assert len(model.licenses) == 1
+
+    model.removeLicense("A00001", "01")
+    assert model.licenses == []
+
+    in_place = tmp_path / "appdata" / "licenses" / "A00001-01.bin"
+    assert model.loadLicenseFile(str(in_place)) is True
+    assert len(model.licenses) == 1
+
+
 def test_model_load_rejects_invalid(tmp_path, qapp):
     src_dir = tmp_path / "dl"
     src_dir.mkdir()
@@ -167,6 +224,23 @@ def test_replay_state_none_then_temporary(tmp_path, qapp):
     assert model.replayTrialExpired() is False
 
 
+def test_start_replay_trial_does_not_reset_existing_marker(tmp_path, qapp):
+    """Repeat calls must not push the clock forward — the original
+    touch(exist_ok=True) bumped mtime on every call, which would let anyone
+    re-trigger the trial start (e.g. an over-limit wafer re-detected) reset
+    the 30-day window indefinitely."""
+    model = LicenseModel(str(tmp_path))
+    assert model.startReplayTrial() is True
+    first_mtime = model._trial_marker.stat().st_mtime
+
+    # Simulate the marker being old (as if most of the trial has elapsed).
+    old_time = first_mtime - 25 * 86400
+    os.utime(model._trial_marker, (old_time, old_time))
+
+    assert model.startReplayTrial() is True
+    assert model._trial_marker.stat().st_mtime == old_time
+
+
 def test_replay_state_permanent_with_level1(tmp_path, qapp):
     (tmp_path / "licenses").mkdir()
     write_license(tmp_path / "licenses", level="01")