I seem to notice this after several hours of gameplay, never had it happen very quickly in a session:
I do a SAVE (either a quicksave <ctrl>s or a Save with me naming the file) and I get a message complaining that the file did not write properly because of a HDD (sic) error. Presuming this is "Hard Disk Drive". Occasionally the <ctrl>s will do nothing when I expect it to save - that's when I know I better use the SAVE menu the old fashioned way and "clean up" (see below).
Whenever this happens, I go back to the SAVE menu and delete the file with the ".tmp" suffix (using the little garbage can next to the name). If the problem happens with a quicksave, I delete ALL the quicksave1-5 files so that I can start using quicksave again.
The behavior is sporatic, and aside from it only happening after I've been playing for a few hours, I can't put my finger on any causal agents.
I've never had .tmp files turn up the next day (as indicated in other threads) and since I'm now in the habit of saving very frequently (and occasionally multiple times at one spot) I haven't suffered any great losses!
Anyhow ... FYI. Still loving the game!
=Gneen