diff --git a/datastore_server/source/java/ch/systemsx/cisd/openbis/dss/client/api/gui/AbstractSwingGUI.java b/datastore_server/source/java/ch/systemsx/cisd/openbis/dss/client/api/gui/AbstractSwingGUI.java
index 4c09fccb81cf7203d7a7764dc546ed9641d38265..9d87b79b6540739a57a59236ba6bb8cc8c5d16e5 100644
--- a/datastore_server/source/java/ch/systemsx/cisd/openbis/dss/client/api/gui/AbstractSwingGUI.java
+++ b/datastore_server/source/java/ch/systemsx/cisd/openbis/dss/client/api/gui/AbstractSwingGUI.java
@@ -237,15 +237,21 @@ public abstract class AbstractSwingGUI
         final Throwable th =
                 (throwable instanceof Error) ? throwable : CheckedExceptionTunnel
                         .unwrapIfNecessary((Exception) throwable);
-        SwingUtilities.invokeLater(new Runnable()
-            {
-                public void run()
+        if (throwable instanceof ClassCastException)
+        {
+            System.err.println("Encountered ClassCastException problem.");
+        } else
+        {
+            SwingUtilities.invokeLater(new Runnable()
                 {
-                    JOptionPane.showMessageDialog(parentFrame,
-                            WordUtils.wrap(message, MESSAGE_WRAP_MAX_CHAR), title,
-                            JOptionPane.ERROR_MESSAGE);
-                }
-            });
+                    public void run()
+                    {
+                        JOptionPane.showMessageDialog(parentFrame,
+                                WordUtils.wrap(message, MESSAGE_WRAP_MAX_CHAR), title,
+                                JOptionPane.ERROR_MESSAGE);
+                    }
+                });
+        }
         th.printStackTrace();
     }