Access 2010 crashing

I've recently moved to Access 2010 and have hit a really annoying problem: when working in form design every now and then it crashes for no apparent reason and won't let me back into design view or the coding window. The forms will still work, I just can't edit them. If I go back to an earlier version I can make the changes, so it's nothing to do with what I am trying to do and I have also discovered that if I make a copy of the offending DB I can open it and carry on from where I left off even though the original still won't let me. Any ideas - I can work with it as long as I keep making copies but it is frustrating