Do you have a crash.log file in your game directory? If so then it is a bug, and could you attach that file here? (maybe the Alpha 10 day 1 hotfix didn't catch all cases of that issue, though it did fix in the case that I found)
If you don't have a crash.log, then maybe something changed in your OS permissions that is preventing them from being saved to disk?
Alternatively, if it's just an error rather than a crash bug (unlikely, but not impossible), after a complete run (and the issue happens) you could attach the run.log file here and I could check if there are any problems. But it won't be able to tell me if it's an OS-side block.
(Also, to make absolute sure, download the
hotfix anyway, just in case!)
Thanks and hopefully we can get this sorted!