Problem with backing up firefox data
Background: On August 6th morning EST after the August 5 2026 update, attempting to use firefox lead to the window with the "end process" button so I had to close the browser multiple times and then the next time I opened firefox, the bookmarks and history were wiped. I was able to restore using a backup saved on the computer and continue as normal (aside from losing some Cookie Clicker progress, reinstalling Tampermonkey userscripts, and redoing browser extension settings) but now there's an issue with trying to backup firefox data.
Issue: Trying to back up my firefox data leads to a "There was a problem backing up. Try again in a few minutes."
When going to about:config and typing browser.backup.backup-debug-info, I get {"lastBackupAttempt":1786243812,"errorCode":9,"lastRunStep":13}
When looking at Broswer Console, there is an entry saying BackupService: Could not create C:\Users\USERNAME\Documents\Restore Firefox\desktop.ini: NotAllowedError: Could not write to `C:\Users\USERNAME\Documents\Restore Firefox\desktop.ini': failed to open file for writing (NS_ERROR_FILE_ACCESS_DENIED) BackupService.sys.mjs:4116:23 but I don't know how to address that.
All Replies (10)
Hi,
Does the issue persist of you run Firefox as administrator? Restart your PC?
Yes. Even turning off my computer, turning it back on, and trying to backup again, or turning off and turning on backup and attempting backup again doesn't change the result. There's only one user on the computer. I'm worried about the browser being corrupted and having to uninstall and reinstall and redoing settings so I haven't tried that yet.
Modified by BM
If you have the Restore Firefox folder (in C:\Users\USERNAME\Documents\Restore Firefox\), can you try deleting/renaming it and see what happens (to force Firefox create a new one)?
Renamed the folder and got the same result. A new Restore Firefox folder does get created but no new backup is made.
Just to be sure no access privilege got weird when updating — could you please download the normal installer from firefox.com and run it over your current setup? It might be able to iron out some permission wrinkles…
Downloaded the Firefox installer from firefox.com, opened it and waited for installer to finish, browser opened by itself, attempted backup again and still got the issue even after manually closing and opening browser as administrator. I hadn't uninstalled Firefox before using the Installer
Modified by BM
Thanks. That might be best reported as a bug.
Is your USERNAME folder/path reasonably named, as in, no "Foo !! … @#$^{} 🚀" or "không bị phân tâm" and similar interesting things to look into?
jbr said
Thanks. That might be best reported as a bug. Is your USERNAME folder/path reasonably named, as in, no "Foo !! … @#$^{} 🚀" or "không bị phân tâm" and similar interesting things to look into?
It uses only lowercase letters and no spaces like abcd. When I copypasted the filepath for posting on here, I replaced the name with USERNAME for privacy.
Yep that's fine, not asking for exact path, just the general pattern, thanks for confirming.
Wasn't able to find any bug on file, could you please report that directly to this component: bugzilla.mozilla.org/enter_bug.cgi?product=Firefox&component=Profile%20Backup ? Thanks.
Reported bug. URL is https://bugzilla.mozilla.org/show_bug.cgi?id=2062094
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