Hi,
I've done this already, but unfortunately I cannot find any copy back. It's an Ubuntu machine (from my girlfriend). Cannot find a copy in the tmp folder, nor can I find it anywhere else on the file system

I've activated now the 'create backup' option in Calc, which should prevent this in future (this is unfortunately not solving the current problem).
I've just heard there was apparently a short power cut yesterday, before the problem occurred, during a thunderstorm. Might be the cause of the problem I'm afraid...