Firefox Community Forum

Hi Moz Support,

I've had this happen several times before, but this time it really annoyed me.

I sent tabs from one Firefox instance to another on another device. I closed these tabs on the source device. These tabs were quite old this time, I'd not opened them in a while - this becomes important later.

On the destination device, let's call it "madbilly's destination Firefox", these tabs didn't arrive. After doing a couple of tests where I sent a tab from my mobile to this instance, I realised that this was a similar problem to what I'd had before, which is one where a Firefox instance/profile for some reasons "resets" itself and it seems to create a new instance in Firefox Sync. Tabs which have previously been sent to "madbilly's destination Firefox" don't arrive, because (I think) it's not registered in Firefox Sync as the same instance. These sent tabs, if closed on the source instance (which I did) are lost, unless one reopens the source instance and Ctrl-Shift+T reopens closed tabs. Unfortunately, in this case because the tabs were old and I hadn't opened them for a while there was no way to do this, because Firefox doesn't remember closed tabs which are not stored in memory (another bug, any fix?), except for looking in old session store backups which I'm going to do after I write this post, though I don't know if that will work.

Also, on Android, because it only remembers 10 closed tabs it's not really feasible to retrieve lost sent tabs this way either, and as there's no access to the session store backups the tabs are definitely lost.

Oddly, when this happens "madbilly's destination Firefox" usually appears twice in the send-tab-to menu, but in this case it didn't. To be able to send to this instance I had to sign out of Firefox sync on this instance and sign in again. Then the same instance appeared twice in the sync menu, the old one being now unreachable.

I'd like to know: 1. Why does this happen? 2. How to avoid it happening? 3. Is there a bug registered about this? 4. When will it be fixed and prevented from happening again.

I generally find that this happens when a Firefox instance isn't shut down properly, which on my old desktop I put down to it running out of resources, but on this shiny new laptop from work that doesn't make sense.

All help much appreciated thanks :)

День добрый. Я с 2023 года не выходил с аккаунта. После переустановки системы, и установки новой версии браузера, синхронизация не подтягивает мои данные (закладки, пароли и тд). Данные очень важны, мне остро необходимо их вернуть.

Subject: Firefox Sync appears to have erased all bookmarks after setting up a new Windows installation

Hello Mozilla Support,

I believe I have encountered a Firefox Sync issue that resulted in the loss of my entire bookmarks collection.

Here is exactly what happened:

I have been using Firefox Sync for several years without any issues. This was not my first Windows reinstallation. I have restored Firefox through Sync multiple times before. Firefox Sync had always synchronized bookmarks, passwords, history, extensions and open tabs correctly across my Windows PC and Android phone. I had approximately 350 bookmarks, organized into folders. Timeline Yesterday I performed a clean installation of Windows 11. I installed Firefox 152.0.5 (64-bit). I signed into my existing Firefox Account. I did not immediately enable Sync, so nothing was synchronized at that point. Today I enabled Sync and waited for the synchronization to complete. Passwords synchronized successfully. Browsing history synchronized successfully (it took a little longer). Extensions were restored successfully. Bookmarks never appeared.

Immediately after noticing this, I checked Firefox on my Android phone.

At first, one of the bookmark folders still showed that it contained more than 300 items (I saw the item count), but when I opened the folder it was completely empty. After synchronization finished, all bookmarks disappeared from both devices.

Additional information Browsing history is still present. Saved passwords are still present. Extensions are still present. Open tabs synchronization continues to work. Bookmark synchronization is enabled. I am signed into the correct Firefox Account. The second local Firefox profile is empty. The automatic bookmark backup now contains only the current state (7 items), indicating that the original backup has already been overwritten. The current profile contains both places.sqlite and places.sqlite-wal. The only Sync error log is related to a temporary DNS lookup failure (NS_ERROR_UNKNOWN_HOST) and contains no bookmark synchronization errors.

Because history, passwords and extensions synchronized correctly, this does not appear to be an account or authentication problem.

What concerns me most is that I briefly saw the bookmark folder still reporting over 300 items on Android before it became empty. This makes me suspect that something went wrong during bookmark synchronization rather than the bookmarks simply never existing on the server.

Could you please advise:

Is there any server-side recovery or investigation that can be performed for Firefox Sync bookmark data? Are there any diagnostic logs that I can provide? Is this a known issue with Firefox Sync after connecting a newly installed device?

I would greatly appreciate any assistance, as this bookmark collection had been accumulated over many years.

I have a Sync error log available: error-sync-1783454370913.txt

It only contains a DNS error related to tabs synchronization: NS_ERROR_UNKNOWN_HOST

There are no bookmark-related errors in the log.

Thank you.