Going to bump this because it is an issue that needs to be fixed asap, running version 1.10.5 and just lost a days work because it wouldn't allow me to save the file anywhere, I tried C:/, D:/, E:/, F:/, sub folders, external drives, usb, and yet it still failed to save the file because it could not be written to, after a while of trying to save, it would pop up a message saying it is now corrupt and will need to close, automatically closing my workstation without any way to stop it.
Made even greater by the lack of autosave meaning if its gone its gone forever, really wished I just stuck to PS at this point.
The steps to replicate this:
Open affinity designer -> make file -> save file -> "failed to save document, save failed because the file could not be written to"
I know its not to do with any interfering software as I have tried it on a clean install of windows as well. Any other apps will save bar affinity's collection.