I have the same problem now affinity crashes when selecting save as started doing this some weeks ago.
Is there none from the company interested in fixing this and adding autosave backup folder options for normal work.
For you with many Questions Yes I disabled controlled folder no change, Yes I added Aff phoro as allowed to make changes to controlled folder. I have tried to turn firewall off.
When I select SAVE AS the affinity program crashes and closes, I can find the file in recent files and reopen it but no luck with saving.
It has been long thread and no fixes I suggest that some clever computer geek could find the phone number of the CEO or COO of affinity.serif.com , serif company and we will take turn calling them and asking them politely to fix this problem. I will bet you after 3 days of 24 hours of answering the phone they will go straight to fixing the problem no one should be rude. just politely as if the could see to it that the problem will be fixed thank you very much.
It seems that is the only way to address the problem