synchronization
I used Firefox on Windows 10 and I had it synchronized after reinstalling the system, despite logging in to my Firefox account, it does not sync, I do not have anything (bookmarks, settings, passwords, themes, plugins, etc.)
ప్రత్యుత్తరాలన్నీ (1)
Just a messenger...
If you don't have access to your old Firefox data on your c drive, then it's all gone. Sync is used to sync your data across different devices. https://support.mozilla.org/en-US/kb/how-do-i-set-sync-my-computer