--- a/AbstractSourceCodeManager.st	Mon Mar 21 04:40:27 2016 +0000
+++ b/AbstractSourceCodeManager.st	Wed Mar 23 22:00:26 2016 +0100
@@ -459,7 +459,7 @@
 
     extensionsRevisionInfo := self revisionInfoFromString:extensionsRevisionString inClass:nil.
     extensionsRevisionInfo isNil ifTrue:[
-        self halt:'oops - possibly corrupted extensions version string'.
+        self halt:('oops - possibly corrupted extensions version string: "%1" in class %2' bindWith:extensionsRevisionString with:defClass name).
         "/ check for umlaut-remover/adder bug from felix in extensionsRevisionString !!!!!!!!
         ^ self streamForClass:nil fileName:fileName revision:nil directory:dir module:mod cache:false.
     ].