The problem is a corrupt file, not much can be done to save these once it happens.
Think of it like a spreading disease. The vector information in the file has been exposed and may be contaminated, so it must all be quarantined. The Raster information is immune, so is safe to trasfer to a new file. The fact is, some of the vector information may be perfectly safe and not yet sick. But just because a vector layer isn't showing symptoms doesn't mean it isn't infected. If you try to move these layers to a new file, it is likely that they will corrupt the new file as well, thus doubling up your loses.
Thanks Brett. I take your point. Is there anything I can do to safeguard against this for the future? Is there any information being found about the cause? Are lots of people having this issue? At this point anything you tell me will simply make me feel better. I understand I'll need to rebuild the file.
Thanks for the response,
The safeguard against this particular issue is to keep Photoshop up to date. This was caused by a bug in the application that we were able to catch and repair. Unfortunately, files already infected are not saved by working with it in the updated application unfortunately.