diff --git a/src/main/java/info/istlab/IoTP/SerialWindow.java b/src/main/java/info/istlab/IoTP/SerialWindow.java
index a9a4f94..cd5b7ff 100644
--- a/src/main/java/info/istlab/IoTP/SerialWindow.java
+++ b/src/main/java/info/istlab/IoTP/SerialWindow.java
@@ -13,6 +13,7 @@
 import java.awt.event.KeyListener;
 import java.awt.event.WindowEvent;
 import java.awt.event.WindowListener;
+import java.util.ArrayList;
 import java.util.Hashtable;
 
 import javax.swing.JFrame;
@@ -304,13 +305,17 @@
     }
 
     public static void disposeAll() {
+        ArrayList<SerialWindow> toberemoved = new ArrayList<SerialWindow>();
         SerialWindow.hash.entrySet().forEach(ent -> {
             // String key = ent.getKey();
             SerialWindow swin = ent.getValue();
             if (swin != null) {
-                swin.disposeWin();
+                toberemoved.add(swin);
             }
         });
+        for (SerialWindow swin : toberemoved) {
+            swin.disposeWin();
+        }
         // SerialWindow.hash.clear();
     }