Index: /trunk/src/VBox/ValidationKit/testmanager/batch/virtual_test_sheriff.py
===================================================================
--- /trunk/src/VBox/ValidationKit/testmanager/batch/virtual_test_sheriff.py	(revision 64944)
+++ /trunk/src/VBox/ValidationKit/testmanager/batch/virtual_test_sheriff.py	(revision 64945)
@@ -748,4 +748,7 @@
                             len(sVgaText)   if sVgaText is not None else 0,
                             len(sInfoText)  if sInfoText is not None else 0, ));
+            if sVMLog is None:
+                sVMLog = '';
+
             #self.dprint(u'main.log<<<\n%s\n<<<\n' % (sResultLog,));
             #self.dprint(u'vbox.log<<<\n%s\n<<<\n' % (sVMLog,));