diff --git a/src/main/java/org/micromanager/lightsheetmanager/LightSheetManagerPlugin.java b/src/main/java/org/micromanager/lightsheetmanager/LightSheetManagerPlugin.java
index 2c4aa771..bacc1e97 100644
--- a/src/main/java/org/micromanager/lightsheetmanager/LightSheetManagerPlugin.java
+++ b/src/main/java/org/micromanager/lightsheetmanager/LightSheetManagerPlugin.java
@@ -14,7 +14,7 @@ public class LightSheetManagerPlugin implements MenuPlugin, SciJavaPlugin {
     public static final String copyright = "Applied Scientific Instrumentation (ASI), 2022-2026";
     public static final String description = "A plugin to control various types of light sheet microscopes.";
     public static final String menuName = "Light Sheet Manager";
-    public static final String version = "0.6.8";
+    public static final String version = "0.6.9";
 
     private Studio studio_;
     private LightSheetManager model_;
diff --git a/src/main/java/org/micromanager/lightsheetmanager/gui/components/TextField.java b/src/main/java/org/micromanager/lightsheetmanager/gui/components/TextField.java
index 6e0e49aa..fc263381 100644
--- a/src/main/java/org/micromanager/lightsheetmanager/gui/components/TextField.java
+++ b/src/main/java/org/micromanager/lightsheetmanager/gui/components/TextField.java
@@ -1,24 +1,99 @@
 package org.micromanager.lightsheetmanager.gui.components;
 
 import javax.swing.JTextField;
+import javax.swing.event.DocumentEvent;
+import javax.swing.event.DocumentListener;
+import java.awt.Color;
+import java.util.function.Consumer;
 
 public class TextField extends JTextField {
 
+    private static final String ILLEGAL_FILENAME_CHARS = "\\/:*?\"<>|";
+    private static final Color ERROR_COLOR = new Color(110, 25, 25);
+
+    private final Color defaultColor_;
+
     public TextField() {
         setColumns(5);
+        defaultColor_ = getBackground();
     }
 
     public TextField(final int size) {
         setColumns(size);
+        defaultColor_ = getBackground();
     }
 
     public TextField(final String text, final int size) {
         super(text);
         setColumns(size);
+        defaultColor_ = getBackground();
     }
 
     public void registerListener(final Runnable listener) {
+        // fires when enter is pressed
         addActionListener(e -> listener.run());
     }
 
+    /**
+     * Registers a listener that validates the current text as a Windows
+     * filename whenever the document changes.
+     *
+     * @param listener receives {@code true} if the current text is valid
+     */
+    public void registerFilenameValidationListener(final Consumer<Boolean> listener) {
+        final Runnable validate = () -> {
+            final boolean isValid = isValidWindowsFilename(getText());
+            setBackground(isValid ? defaultColor_ : ERROR_COLOR);
+            listener.accept(isValid);
+        };
+
+        final DocumentListener docListener = new DocumentListener() {
+            @Override
+            public void insertUpdate(DocumentEvent e) {
+                validate.run();
+            }
+
+            @Override
+            public void removeUpdate(DocumentEvent e) {
+                validate.run();
+            }
+
+            @Override
+            public void changedUpdate(DocumentEvent e) {
+                validate.run();
+            }
+        };
+
+        getDocument().addDocumentListener(docListener);
+    }
+
+    /**
+     * Returns {@code true} if the filename is valid on Windows.
+     *
+     * @param name the name to check
+     * @return {@code true} if the filename is valid
+     */
+    private static boolean isValidWindowsFilename(final String name) {
+        // empty names are invalid
+        if (name.isEmpty()) {
+            return false;
+        }
+
+        // trailing space or period
+        final char last = name.charAt(name.length() - 1);
+        if (last == ' ' || last == '.') {
+            return false;
+        }
+
+        // check for illegal characters and control characters
+        for (int i = 0; i < name.length(); i++) {
+            final char c = name.charAt(i);
+            // c < 32 rejects all ASCII control characters (0x00–0x1F)
+            if (c < 32 || ILLEGAL_FILENAME_CHARS.indexOf(c) >= 0) {
+                return false;
+            }
+        }
+
+        return true;
+    }
 }
diff --git a/src/main/java/org/micromanager/lightsheetmanager/gui/tabs/acquisition/SavePanel.java b/src/main/java/org/micromanager/lightsheetmanager/gui/tabs/acquisition/SavePanel.java
index dfa10e51..c6df7662 100644
--- a/src/main/java/org/micromanager/lightsheetmanager/gui/tabs/acquisition/SavePanel.java
+++ b/src/main/java/org/micromanager/lightsheetmanager/gui/tabs/acquisition/SavePanel.java
@@ -164,6 +164,13 @@ public void createEventHandlers() {
                 () -> model_.acquisitions().settingsBuilder()
                         .saveNamePrefix(txtSaveFileName_.getText()));
 
+        txtSaveFileName_.registerFilenameValidationListener(isValid -> {
+            if (isValid) {
+                model_.acquisitions().settingsBuilder()
+                        .saveNamePrefix(txtSaveFileName_.getText());
+            }
+        });
+
         cbxSaveMode_.registerListener(
                 () -> model_.acquisitions().settingsBuilder()
                         .saveMode(cbxSaveMode_.getSelected()));
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 02a3a28c..670280c2 100644
--- a/src/main/java/org/micromanager/lightsheetmanager/model/acquisitions/AcquisitionEngineScape.java
+++ b/src/main/java/org/micromanager/lightsheetmanager/model/acquisitions/AcquisitionEngineScape.java
@@ -241,7 +241,9 @@ boolean run() {
 
         // TODO: put this in AcquisitionEngine base class, between setup and run once structure is better
         // save settings as JSON to the save directory
-        FileUtils.writeStringToFile(saveDir + File.separator + "acq_settings.json", settingsJson);
+        if (model_.acquisitions().settings().isSavingImagesDuringAcquisition()) {
+            FileUtils.writeStringToFile(saveDir + File.separator + "acq_settings.json", settingsJson);
+        }
 
         // write the position list if we are using multiple positions
         if (model_.acquisitions().settings().isUsingMultiplePositions()) {