This is my MAJOR issue with sync!!! There is no logic or prompt and it just runs as soon as you login.

My issue ---> https://support.mozilla.org/en-US/questions/1312258

Your issue is that after doing the clean install, you opened the browser and signed into a fresh and clean Firefox. Guess what... that is what synced and now there is nothing.

Here is what I was told when I opened a bug... Bug ---> https://bugzilla.mozilla.org/show_bug.cgi?id=1677090

"This behavior is deliberate - the "synced tabs" feature is for showing tabs that you currently have open on other devices, and is not designed for viewing historical tabs from the current device. If we showed the current device in that list, it would only display the tabs that you currently have open, which doesn't seem useful."

I spoke about this very issue. What will happen if a person has only 1 computer and reinstall for whatever reason and they will naturally think that their Firefox data is backed up or synced.

Yes, this is exactly the issue. I'm sure Mozilla must have some kind of back up on their servers, and in extreme circumstances, how do we solve this?

Did you verify that all your data has been uploaded to the Sync server as this doesn't happens instantly and can take hours or maybe a day if there is a lot of data that needs to be uploaded ?

Also keep in mind that Sync isn't meant to be used as a backup.

If you use the Time Machine or other backup then try to restore file(s) from this backup.

• https://www.apple.com/support/timemachine/

You can install the About Sync extension in Firefox 72 and newer on desktop to check what data is stored on the Sync server via the about:sync page provided by this extension.

• About Sync https://addons.mozilla.org/firefox/addon/about-sync/

Close and restart Firefox to access the about:sync page added by this extension (see the about:about page for possible about pages).

Yes, right before I re-installed the OS, the sync was complete. Unfortunately due to low storage I had not used the time machine back up. I just tried using the about sync add on to check the logs, but the earliest entries are from the fresh Mozilla browser and nothing from before that. Yes I found out that sync was an unreliable option to back up, but that was far too late. In the Firefox preferences, it did say that bookmarks, history etc would be synced, so I assumed it would be to a cloud. Should have read more carefully I think. Is there absolutely no way to recover the lost data in this scenario? Thank you for your help.

I wouldn't say that it's unreliable, but in need of more logic. Right now it just syncs with out any prompts before doing so. The day I opened my browser and saw my 30+ tabs gone, the sync took place and when I went to another computer it only showed the 1 tab.

I think that there should have been some kind of prompt to say "Hey, we noticed that the sync in progress is smaller than the previous sync. Do you want to proceed?" Something like that...  ;-))