I recently had to recover a corrupt central model file which turned out to be way more corrupt than one would have hoped for.

The usual recovery attempts would include recovering from the Collaborate ribbon menu items:

Restore backups allows you to attempt to save / restore a previous version of the central model. I usually save a previous model rather than "rolling back", after which I first inspect the model before restoring it manually as the central model again.

In this case, no success, the model seemed to be corrupt for all previous versions, which was strange, since the user worked on it without problems apart from the latest revision.

I also tried the Audit option with opening, in various combinations with Detach from Central and Keeping or Discarding Worksets - No luck. The model would actually open, but when I try to save it, with or without purging, it would crash. No file or recovery file saved.

After some research and suggestions from various sources (thanks Gary Page from CADPro), I opened the central model (a version from the Restore Backup feature) using Audit, no other way it would open, Detach from Central and preserving the worksets. 

I then used the Save As => Library = > Family to save all loaded families to an external location (temporary). The purpose of this was to see whether a n error would pop up during the saving process, then to note the family / families that has the error.

After the process has completed, I removed these problematic families from the model, using the project Browser, then purged and saved the model again as a new central model.

Note: It is also good to empty your Windows Temp folder (type %temp% in your Windows Explorer path) before trying to recover.

 

Best of luck.