"Could notS create file" backup problem

When I quit Scrivener on my PC, it creates a Zip backup with no problems. I use Dropbox to synchronise everything between my computers (both Windows 10). When I open my Scrivener project on my laptop, everything is fine, but when I quit it says "Could not create backup file [filename] Could not create file at: [location]. It only just started to do this – been working fine up until now. I noticed that some of the files in the backup location were read only, so I changed them into regular files: I still get the same error, but now Scrivener goes 50% through creating the back up file (it quit immediately before), then I get the “could not create backup file” error, but the "Creating backup dialog is still open. Everything is now frozen and I have to abort the backup to quit. However, if I save my backups in a different location, it backs up fine.

Any idea why this is happening?

I had this issue within a single computer. One project would back up; another would not.

I finally gave up, created a new project, transferred information into the new project (drag/drop), saved it as a new file, and then it worked.

It sounds like a permissions issue. When I examined the original files I was having issues with, they turned out to be copies I had transferred from another computer, with different usernames attached. I could open them, I could save to them, but I could not back them up because they belonged to the wrong user. You’d think I wouldn’t be able to open them, but I could. I don’t know why Scrivener/Windows did this, but it did.

I also created and used a different backup file location, instead of using the Appdata default (I don’t want my backups at the end of a long string of pathname).

I hope that helps.