Files disappearing

I was working on a cpt with a few lenses on a background object. Save as jpg, and the original cpt is now gone.

I was working off my desktop. Using X7 64bit SP3 on W7, beefy machine.
It happened more than once but I can't get it to happen every time.

Only once was after saving a jpg, the other time was just saving and closing, and the file just is gone.

I went to the recent files list and it was there, but choosing it didn't work, said it was missing.

No files in the temp folder either.

What a bummer -- I lost 2 files and they took me hours.

Anyone else?

Thanks,

joan