diff --git a/src/main/java/org/micromanager/lightsheetmanager/gui/LightSheetManagerFrame.java b/src/main/java/org/micromanager/lightsheetmanager/gui/LightSheetManagerFrame.java
index 495651c..d6a67ad 100644
--- a/src/main/java/org/micromanager/lightsheetmanager/gui/LightSheetManagerFrame.java
+++ b/src/main/java/org/micromanager/lightsheetmanager/gui/LightSheetManagerFrame.java
@@ -47,6 +47,7 @@ public LightSheetManagerFrame(final LightSheetManagerModel model, final boolean
 
         // create the user interface
         if (isLoaded) {
+            initDialogs();
             GeometryType geometryType = model_.devices()
                     .getDeviceAdapter().getMicroscopeGeometry();
             switch (geometryType) {
@@ -139,7 +140,7 @@ private void createUserInterface() {
         WindowUtils.registerWindowClosingEvent(this, event -> {
             tabPanel_.getNavigationTab().getNavigationPanel().stopPolling();
             model_.getUserSettings().save();
-            System.out.println("main window closed!");
+            studio_.logs().logMessage("user settings saved");
         });
 
     }
@@ -153,6 +154,14 @@ public Studio getStudio_() {
         return studio_;
     }
 
+    /**
+     * Detect settings after the model is loaded,
+     * ask to change settings with dialogs.
+     */
+    private void initDialogs() {
+        model_.devices().checkDevices(this);
+    }
+
     public void toggleLiveMode() {
         if (studio_.live().isLiveModeOn()) {
             studio_.live().setLiveModeOn(false);
diff --git a/src/main/java/org/micromanager/lightsheetmanager/gui/utils/DialogUtils.java b/src/main/java/org/micromanager/lightsheetmanager/gui/utils/DialogUtils.java
index ccf5b7d..01ba48d 100644
--- a/src/main/java/org/micromanager/lightsheetmanager/gui/utils/DialogUtils.java
+++ b/src/main/java/org/micromanager/lightsheetmanager/gui/utils/DialogUtils.java
@@ -32,6 +32,10 @@ public static String showTextEntryDialog(final JFrame frame, final String title,
                 JOptionPane.PLAIN_MESSAGE, null, null, "");
     }
 
+    public static int showYesNoDialog(final JFrame frame, final String title, final String message) {
+        return JOptionPane.showConfirmDialog(frame, message, title, JOptionPane.YES_NO_OPTION);
+    }
+
     /**
      * Shows a customized message dialog box, this method does not log the error.<P>
      * This is used for reporting errors in the AcquisitionTable.
diff --git a/src/main/java/org/micromanager/lightsheetmanager/model/DeviceManager.java b/src/main/java/org/micromanager/lightsheetmanager/model/DeviceManager.java
index 2f1a414..5eb623a 100644
--- a/src/main/java/org/micromanager/lightsheetmanager/model/DeviceManager.java
+++ b/src/main/java/org/micromanager/lightsheetmanager/model/DeviceManager.java
@@ -6,6 +6,7 @@
 import mmcorej.CMMCore;
 import mmcorej.DeviceType;
 import org.micromanager.Studio;
+import org.micromanager.lightsheetmanager.gui.utils.DialogUtils;
 import org.micromanager.lightsheetmanager.model.devices.DeviceBase;
 import org.micromanager.lightsheetmanager.model.devices.Galvo;
 import org.micromanager.lightsheetmanager.model.devices.LightSheetDeviceManager;
@@ -24,6 +25,7 @@
 import org.micromanager.lightsheetmanager.model.devices.vendor.ASIXYStage;
 import org.micromanager.lightsheetmanager.model.devices.vendor.ASIZStage;
 
+import javax.swing.JFrame;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.Map;
@@ -419,4 +421,37 @@ private ArrayList<String> updateConfig(final String groupName, final String conf
         return newProperties;
     }
 
+    // TODO: adapt for diSPIM and multiple cameras
+    /**
+     * Check user settings and ask to change settings with dialogs.
+     */
+    public void checkDevices(final JFrame frame) {
+
+        final String cameraKey = "ImagingCamera";
+        CameraBase cameraDevice = getDevice(cameraKey);
+        CameraLibrary cameraLib = CameraLibrary.UNKNOWN;
+        if (cameraDevice != null) {
+            cameraLib = CameraLibrary.fromString(cameraDevice.getDeviceLibrary());
+        }
+
+        switch (cameraLib) {
+            case HAMAMATSU:
+                // Flash4, Fusion, etc
+                HamamatsuCamera camera = getDevice(cameraKey);
+                if (camera.getTriggerPolarity().equals(HamamatsuCamera.Values.NEGATIVE)) {
+                    final int result = DialogUtils.showYesNoDialog(frame, "Hamamatsu Camera",
+                            "The trigger polarity should be set to POSITIVE. Set it now?");
+                    if (result == 0) {
+                        camera.setTriggerPolarity(HamamatsuCamera.Values.POSITIVE);
+                    }
+                }
+                break;
+            case PVCAM:
+                // Kinetix, etc
+                break;
+            default:
+                break;
+        }
+    }
+
 }
diff --git a/src/main/java/org/micromanager/lightsheetmanager/model/acquisitions/AcquisitionEngineSCAPE.java b/src/main/java/org/micromanager/lightsheetmanager/model/acquisitions/AcquisitionEngineSCAPE.java
index 301436b..721fb0a 100644
--- a/src/main/java/org/micromanager/lightsheetmanager/model/acquisitions/AcquisitionEngineSCAPE.java
+++ b/src/main/java/org/micromanager/lightsheetmanager/model/acquisitions/AcquisitionEngineSCAPE.java
@@ -55,6 +55,12 @@ public AcquisitionEngineSCAPE(final LightSheetManagerModel model) {
     @Override
     boolean setup() {
 
+        // this is needed for LSMAcquisitionEvents to work with multiple positions
+        if (core_.getFocusDevice().isEmpty()
+                && acqSettings_.isUsingMultiplePositions()) {
+            studio_.logs().showError("The default focus device \"Core-Focus\" needs to be set to use multiple positions.");
+        }
+
         // make sure that there are positions in the PositionList
         if (acqSettings_.isUsingMultiplePositions()) {
             final int numPositions = studio_.positions().getPositionList().getNumberOfPositions();
diff --git a/src/main/java/org/micromanager/lightsheetmanager/model/devices/cameras/HamamatsuCamera.java b/src/main/java/org/micromanager/lightsheetmanager/model/devices/cameras/HamamatsuCamera.java
index 5165a01..eecdff1 100644
--- a/src/main/java/org/micromanager/lightsheetmanager/model/devices/cameras/HamamatsuCamera.java
+++ b/src/main/java/org/micromanager/lightsheetmanager/model/devices/cameras/HamamatsuCamera.java
@@ -23,6 +23,7 @@ public static class Properties {
         public static final String CAMERA_BUS = "Camera Bus";
         public static final String TRIGGER_SOURCE = "TRIGGER SOURCE";
         public static final String TRIGGER_ACTIVE = "TRIGGER ACTIVE";
+        public static final String TRIGGER_POLARITY = "TriggerPolarity";
         public static final String SENSOR_MODE = "SENSOR MODE";
         public static final String INTERNAL_LINE_INTERVAL = "INTERNAL LINE INTERVAL";
         public static final String SCAN_MODE = "ScanMode";
@@ -39,6 +40,8 @@ public static class Values {
         public static final String PROGRESSIVE = "PROGRESSIVE";
         public static final String AREA = "AREA";
         public static final String USB3 = "USB3";
+        public static final String POSITIVE = "POSITIVE";
+        public static final String NEGATIVE = "NEGATIVE";
         public static final String SCAN_MODE_1 = "1";
         public static final String SCAN_MODE_2 = "2";
         public static final String SCAN_MODE_3 = "3";
@@ -238,4 +241,13 @@ public boolean isFusion() {
     public boolean isFlash4() {
         return getProperty(Properties.CAMERA_NAME).startsWith(Models.FLASH4);
     }
+
+    public String getTriggerPolarity() {
+        return getProperty(Properties.TRIGGER_POLARITY);
+    }
+
+    public void setTriggerPolarity(final String polarity) {
+        setProperty(Properties.TRIGGER_POLARITY, polarity);
+    }
+
 }