Here's a weird thing I've had happen several times. I open an assembly. Open sub-assembly. Open part and edit it (not edit in asm), delete some features, add some new ones. Save and close part. I then get this error message show up:

One of the components of this assembly is in rollback state. The assembly is inaccessible now.

I've never had any part in rollback state at all... any idea what's happening? I can switch between both open asm's but can't edit them or do anything to them. It's completely non-responsive, and won't even save or close. I have to end SolidWorks through Task Manager.