Revit :: Incorrect Schema Error

I was working on a file earlier today when it failed while processing after I edited a particularly extensive mass. It asked if I wanted to save a recovery file, I said yes, but I am not sure it worked properly (it might have said 'could not be saved' but i clicked 'OK' quickly so i could re-open revit and get on with work)
 
Anyways, when I went back to start again it said I had to manually recover the file and that I should ask Autodesk support. I looked on forums and they said i should go to the 'open' dialogue box, check the 'audit' box and reopen the file, but after doing this I got a second error message that said something along the lines of "your file has an incorrect schema'.
 
This project is not part of any collaboration, it's standalone and on my home PC.I couldn't find any email to write to, or number to call, or FAQ, so here I am.
 
This is the third damned problem I've had with this file, might have something to do with a trojan on my computer chewing into my RAM but whatever the case it's time this crap stopped!