diff --git a/src/main/java/de/neemann/digital/gui/SaveAsHelper.java b/src/main/java/de/neemann/digital/gui/SaveAsHelper.java
index 942c380f2..09eac1d04 100644
--- a/src/main/java/de/neemann/digital/gui/SaveAsHelper.java
+++ b/src/main/java/de/neemann/digital/gui/SaveAsHelper.java
@@ -34,6 +34,7 @@ public final class SaveAsHelper {
         KNOWN.add("tt2");
         KNOWN.add("cupl");
         KNOWN.add("jed");
+        KNOWN.add("zip");
     }
 
     private final Component parent;