Engine Crash when opening a project

Hi,
at the moment I have a serious problem: When I opening my project (Unreal Engine 4.7.6) I get a crash. I tried also the new version 4.8 (Preview 3). But the crash appears again. I removed the Blueprint folders in the project and I cleared the autosave folder. But this did not help. What can I do to save my project? I can not understand why such a thing could ever happen.

Best regards, Andreas

UPDATE:
After a restart of my computer I could open the project again without any problems. I guess this is a useful information for everyone who has similar problems.