This is driving me mad...
I'm working from a central model saved to a network server. Upon opening I "Create New Local" and it opens fine. I can make changes with no problem. I've been using the same file for over a month with no issue. However, starting this morning, whenver I try to Save or Sync with Central, Revit crashes with the message "An unrecoverable error has occured. The program will now be terminated."
I've tried detaching from central, and copying the file to another directory. I've updated Revit. I've uninstalled / reinstalled Revit. I've deleted / recreated my user profile. Nothing works.
The same file saves + syncs without issue on other computers. And to make things crazier, similar central model files save + sync without issue on my computer.
WHAT IS GOING ON HERE?!?
Are you running the same build as other users? Have you installed/modified/uninstalled any other software recently? How do your computer specs (graphics card, processor, OS, etc.) compare to the other users (i.e. are all computers identical)?
If you've recreated the central file, and others aren't having the same issues with that file, then that points to your computer being the problem. Beyond what I mentioned above, I don't have much to offer.
You could try resetting the UIState.dat file and removing all the local files in your My Documents (or wherever you have them) and try again.
Update: I seem to have fixed it. Posting here so anyone who might run into similar issues has help.
I came in on Sunday morning while no one else was in the office / connected to the server. I made sure everyone's Revit and OS were updated and on the same versions (installed SP3 on a couple machines).
Then I opened the local file that was able to sync without issue (on a coworker's machine). I detached that from the central, backed up the original central model, and deleted all previous local copies on all machines.
I went through the process of purging the new local file (following these steps: http://blogs.rand.com/support/2012/06/revit-making-a-local-file-the-new-central-file.html), then tested saving the local. That worked without issue so I re-saved this file as a new central model (same name and in the same folder as the archived original).
Finally, I tested opening and saving / syncing on the troubled machines. Everything worked with no issue.
I'm still not sure what caused the problem or why this fix worked, but it worked.