Microsoft has never been a fan of “registry cleaner” CCleaner and now the company has just given Microsoft another reason to keep it in its black books.
The latest public version of CCleaner has been found to delete synched Firefox extensions setting and other data.
This is due to a change in where Firefox 79 stores extension data when you are synching two PCs with Firefox, with the data now being stored in the Profile directory. Unfortunately, CCleaner routinely deletes the contents of the Profile directory, meaning your Extensions data and setting and constantly being deleted.
While this may seem like an honest mistake, the issue has been reported to Piriform in July when Firefox was in Beta, but no action had been taken by the company, with users now losing data with the final release of Firefox 79.
The solution is of course to uninstall CCleaner, but if for some reason you wish to continue using it, you can exclude the relevant files (Storage-sync-v2-sqlite-shm and storage-sync-v2.sqlite-wal ) from the daily purge by going to CCleaner > Options > Excludes > Add > File and adding: