diff --git a/src/main/java/de/neemann/digital/gui/SaveAsHelper.java b/src/main/java/de/neemann/digital/gui/SaveAsHelper.java
index d64f4bc7b..a7191fc93 100644
--- a/src/main/java/de/neemann/digital/gui/SaveAsHelper.java
+++ b/src/main/java/de/neemann/digital/gui/SaveAsHelper.java
@@ -5,6 +5,7 @@
  */
 package de.neemann.digital.gui;
 
+import de.neemann.digital.analyse.quinemc.TableRows;
 import de.neemann.digital.lang.Lang;
 import de.neemann.gui.ErrorMessage;
 
@@ -12,12 +13,27 @@ import javax.swing.*;
 import java.awt.*;
 import java.io.File;
 import java.io.IOException;
+import java.util.HashSet;
 
 /**
  * Helper to handle the overwrite conformation
  * <p>
  */
 public final class SaveAsHelper {
+    private static final HashSet<String> KNOWN = new HashSet<>();
+
+    static {
+        KNOWN.add("dig");
+        KNOWN.add("svg");
+        KNOWN.add("vhdl");
+        KNOWN.add("v");
+        KNOWN.add("hex");
+        KNOWN.add("tru");
+        KNOWN.add("csv");
+        KNOWN.add("gif");
+        KNOWN.add("png");
+    }
+
     private final Component parent;
     private final JFileChooser fc;
     private final String suffix;
@@ -102,8 +118,13 @@ public final class SaveAsHelper {
 
         String name = filename.getName();
         int p = name.lastIndexOf('.');
-        if (p >= 0 && p == name.length() - 4)
-            name = name.substring(0, p);
+        if (p >= 0) {
+            String suf = name.substring(p + 1).toLowerCase();
+            if (KNOWN.contains(suf))
+                name = name.substring(0, p);
+            while (name.length() > 0 && name.charAt(name.length() - 1) == '.')
+                name = name.substring(0, name.length() - 1);
+        }
         return new File(filename.getParentFile(), name + "." + suffix);
     }
 
diff --git a/src/test/java/de/neemann/digital/gui/SaveAsHelperTest.java b/src/test/java/de/neemann/digital/gui/SaveAsHelperTest.java
index 1345b2c8b..697a19404 100644
--- a/src/test/java/de/neemann/digital/gui/SaveAsHelperTest.java
+++ b/src/test/java/de/neemann/digital/gui/SaveAsHelperTest.java
@@ -12,10 +12,17 @@ import java.io.File;
 public class SaveAsHelperTest extends TestCase {
 
     public void testCheckSuffix() {
+        assertEquals("test.dig", SaveAsHelper.checkSuffix(new File("test."), "dig").getName());
+        assertEquals("test.dig", SaveAsHelper.checkSuffix(new File("test"), "dig").getName());
+
         assertEquals("test.dig", SaveAsHelper.checkSuffix(new File("test.dig"), "dig").getName());
         assertEquals("test.dig", SaveAsHelper.checkSuffix(new File("test.svg"), "dig").getName());
         assertEquals("test.main.dig", SaveAsHelper.checkSuffix(new File("test.main"), "dig").getName());
         assertEquals("test.main.dig", SaveAsHelper.checkSuffix(new File("test.main.dig"), "dig").getName());
-        assertEquals("test.dig", SaveAsHelper.checkSuffix(new File("test.mai"), "dig").getName());
+        assertEquals("test.mai.dig", SaveAsHelper.checkSuffix(new File("test.mai"), "dig").getName());
+
+        assertEquals("test.dig", SaveAsHelper.checkSuffix(new File("test.v"), "dig").getName());
+        assertEquals("test.dig", SaveAsHelper.checkSuffix(new File("test.vhdl"), "dig").getName());
+
     }
 }
\ No newline at end of file