[Pharo-users] KeyNotFound: key #nil not found in SystemDicitonary

So, I've been trying to save and close my image for a while now. It won't even just close without saving, it constantly pops up the error from this subject. I'm fairly new to all this, but I followed it to I think an Array of ClassSessionHandlers one of which is ClassSessionHandlers(nil) but I don't know how to get rid of it, I also opened the process browser and found a Morphic UI Process: nil which i tried to terminate. None of which seems to work. How to I get this nil value out of my image save / shutdown process? -- Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html