Hello everyone!

We got a nice little Error occuring lately on a project we just ported to Revit 2014.
Revit suddenly kind of freezes within the current project only (!) with saving/STC no longer available. Changing views to another project/family is still possible and everything seems to be active and working again. So only when trying to work in that one project pretty much everything is greyed out. Has anybody come across this already?
The error ocurred one time when editing a specific model group, but just recently even without any particular action after returning to the Revit window.
When ending Revit through the Task-Manager the underneath message pops up. It somewhat translates like "You tried to execute a non supported action." and the only thing you can do is close Revit.

I'd be very grateful for any advice on how to solve this!

Thanks in advance,

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