Could you please share a lot more information?
The problem in the initial thread is different from yours since it was caused by a bug that was fixed. Plus, you mention something about previews disappearing too which didn't happen with the old bug.
So, please, tell us as much information as you can about your system and describe the problem with more detail too.
Are you still having trouble with this D3lirious? Please let us know if we can be of any assistance.