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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.

Firefox Sync is not syncing bookmarks from Windows to iPhone.

The issue persists even after creating a completely new Firefox Account, creating a new Firefox profile, reinstalling Firefox, and testing on a different network.

Environment Windows 11 Firefox 153.0 (64-bit) Firefox downloaded from mozilla.org (not Microsoft Store) Firefox for iPhone (latest version) VPN disabled Windows Defender only (no third-party antivirus) Problem

Bookmarks created on the iPhone never appear on the Windows PC.

Bookmarks created on the Windows PC also never appear on the iPhone.

The iPhone currently contains more than 1,000 bookmarks.

Tabs and account sign-in appear to work normally, but bookmark synchronization does not.

Troubleshooting already performed Created a new Firefox profile. Reinstalled Firefox. Created a completely new Firefox Account. Signed out and signed back in. Reset Sync. Verified that bookmark sync is enabled. Confirmed services.sync.engine.bookmarks = true. Tested with VPN disabled. Tested using a mobile hotspot instead of the home network. Verified DNS resolution using nslookup. Verified Mozilla servers are reachable from Chrome. Confirmed Firefox DNS settings are default: network.trr.mode = 0 network.dns.disableIPv6 = false Sync log observations

The Sync log reports that bookmark changes are detected:

Sync.Engine.Bookmarks.BookmarkSyncUtils pushChanges: Processed change records: {"updated":9}

However, the log never contains a request similar to:

POST ... /storage/bookmarks

Therefore, bookmark changes appear to be detected locally but are never uploaded to the Sync server.

In different sync attempts, I have also observed intermittent network-related errors such as:

NS_ERROR_NET_RESET NS_ERROR_CONNECTION_REFUSED NS_ERROR_UNKNOWN_HOST

For example:

Failed to fetch symmetric keys. Not syncing: login returned false.

and

The lookup of the hostname failed.

However, DNS resolution and connectivity appear normal outside Firefox:

nslookup successfully resolves Mozilla Sync hosts. ping succeeds. Opening https://profile.accounts.firefox.com/v1/profile from Chrome returns the expected HTTP 401 Unauthorized response ("Bearer token not provided"), indicating the server is reachable. Additional information

Because the iPhone contains more than 1,000 bookmarks, I would also like to know whether Firefox Sync has any known limitations or issues related to synchronizing large bookmark collections.

Expected behavior

Bookmarks created on either device should synchronize to the other device.

Actual behavior

Bookmark changes are detected locally but never uploaded, and no bookmark synchronization occurs in either direction.

I would appreciate any guidance on additional diagnostics or whether this could be a Firefox Sync bug.

I changed my windows and install firefox again, but after I logged to my account I cannot revive my bookmarks and passwords. sync doesn't work for me. I did it several times. but now , it doesn't work.

I'm trying to sync all the bookmarks I have saved in Firefox V 153.0 (aarch64) on my Macbook Pro V 26.5.2 to my Firefox V 153.0 on my iPhone 12 Pro running V 26.5.2

It looks like sync is running, but I can't find my laptop bookmarks on my iPhone?

Is it possible I have more than one firefox account? If so, how do I get rid of one?

Is it possible I'm logged in to Firefox via my Google account? If so, how do I delete that log in?

Sehr geehrtes Support-Team,

ich habe seit Kurzem ein Problem mit Firefox auf meinem PC. Es erscheint folgende Fehlermeldung:

   „Das Lesezeichen- und Chronik-System wird nicht funktionieren, da eine der Dateien von Firefox von einer anderen Anwendung verwendet wird. Dieses Problem könnte von einer Sicherheitssoftware verursacht werden, beispielsweise von einem Virenscanner.“

Ich nutze dasselbe Firefox-Konto auf meinem Handy und auf meinem iPad. Dort funktioniert die Synchronisierung der Lesezeichen ohne Probleme. Das Problem tritt nur auf meinem PC auf.

Ich arbeite bereits seit mehreren Jahren mit Firefox und hatte dieses Problem bisher noch nie. In meinen Lesezeichen sind sehr viele wichtige Webseiten gespeichert, deshalb möchte ich diese auf keinen Fall verlieren.

Können Sie mir bitte mitteilen, wie ich dieses Problem beheben kann, ohne dass meine Lesezeichen verloren gehen?

Vielen Dank für Ihre Unterstützung.

Mit freundlichen Grüßen

Meik

I'm still using the old browser because the new browser, the one before that popped up today, doesn't work well on my old desktop computer. New one today requested to move passwords from cvs file and bookmarks from an html file. When I tried to search for these things my computer couldn't find them. But when I went back to the old browser, all bookmarks passwords are there.

Why is Firefox asking me to perform these functions anyway? There is no explanation as to what this is. Is programming at Mozilla really gone downhill so quickly that they forgot how to make their service user friendly?

I had a phone set up for synchronization, and the tabs were synced. Now, that phone has disappeared from my main phone—the one that listed all the devices—and all the tabs are gone. What should I do?

How can I get my tabs back? 😭

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.

No matter what I do, sometimes, Firefox on my phone won't sync and it's driving me crazy to be honest. I don't know why it happens, it has no fixed schedule and it seems to go away on it's own in a seemingly random amount of time. In this instance, as I'm writing this I've been trying to sync with my PC for over an hour and it simply refuses to sync. I've tried restarting, force stoping , clearing cache.. Nothing. In the past I even tried reinstalling and for it to sync it took a while. I'm lost with this bug and it's been happening for a while now, I was hoping for a fix but so far it seems it hasn't come.

Please let me know if additional information is needed.

For years, I've been using FF on desktop (Linux), tablet (Android) and phone (Android - Samsung S24+). Sync has never been a problem until two weeks ago when FF on the phone has either refused to sync when I tapped the command, or hasn't synced for many hours or sometimes days (which is why I tried to do it manually). So, I signed out of my FF account on all 3 devices and then signed back in. The desktop computer and tablet are syncing normally, but the phone still won't sync. When I tap the 3-dot menu on the phone and then my name, it says the phone has NEVER been synced and tapping the sync command does nothing. Under "Choose what to sync", all options are checked, but greyed out. Can't change them, in other words. When I access bookmarks on the phone, it properly shows what was there before the last sync. The phone is running FF version 150.0 Build 2016155439

Help!

sync not working from: desktop to pixel 10 pro. desktop has folders and subfolders.

In addition sync not working from pixel 6 to desktop. pixel 6 is setup with folders and subfolders. There are approx 300 bookmarks

Installed Firefox on new android. When I try to sign in using sync the camera doesn't recognize the QR code on laptop pair screen, turned up brightness, hold closer and further away etc but just doesn't recognize. If I log in using email my passwords, history etc do not transfer.

Hello everyone .

I have used Firefox for years now and I always keep my sync on. When I sign in to a new device, I sync and all my data. I had a problem with my PC today and I downloaded Firefox for mobile on my Android tab. I tried signing in but forgotten my password, I did a reset and logged in and tried to sync but I can't find my previous data. I can't even see any of my previous devices. This is strange because it has always worked

Any help will be deeply appreciated.