Firefox Community Forum

A month ago, I raised this question, but there was no answer. The problem is still here, and forgive me for posting it again. Maybe this time someone experienced will see it. Let me know if you encounter the same problem, maybe we can discuss it out. And thank you to everyone who spares time to read this post. Below is the original question. I'm a Chinese firefox user, so the following descriptions are translated and may not be so accurate. And the attached image is also Chinese, if necessary please use a translation app or somewhat to see it. I have only one default profile in my Firefox account, and I have stored a large number of passwords and bookmarks in this default profile. For certain reasons, I signed out of this profile while retaining the local data such as passwords—meaning that, apart from not being logged in, my browser state remains exactly the same as before. Now I wish to sign back in to enable synchronization. I can see a "Sync and Save Data" button prompting me to log in. After clicking this button, I am asked to enter my username and password, but then I receive a message stating that I have reached the account limit for this profile, and that this profile was previously synced to another account. This is absurd, as I do not have another account, nor have I ever synced this profile to any so-called other account. As a result, I am unable to sign in on this current profile.

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 :)

Hello,

I updated my version to 153.0. The Bookmarks left panel was there. I did a CTRL+B, this one disapeared normal But once done I wanted to have my Boorkmarl left pannel back. So I did CTRL+B no Bookmark left pannel was displayed :-(

Regards.

Watching any Bilibili live stream causes severe performance issues. The main problems I can observe are intermittent severe mouse cursor stuttering/frame drops or the cursor becoming unresponsive, accompanied by the taskbar process (explorer.exe) intermittently restarting.

I have tried disabling the Picture-in-Picture feature and tampermonkey add-on, modifying the Windows 11 registry to turn off MPO (Multiplane Overlay), adjusting browser hardware acceleration, and tweaking related settings in about:config, but none of these have been able to prevent the issue.

I came to know about Firefox Widgets but can't see any on Firefox 152 on Windows 11 desktop. The option Allow Firefox to improve features, performance and stability between updates is already checked (Screenshot attached) as suggested by users.

Our team has already tried to fix the issue for a week now and none of the approaches seem to fix the issue. Does the Firefox dev department have any hints or clues for us?

Short description: Firefox network.lna.blocking blocks same-origin/loopback requests when the page is controlled by a Service Worker

Symptom: Login via OIDC fails in Firefox (the backend call after the IdP redirect is blocked). The error disappears if either network.lna.blocking=false is set or the Service Worker is disabled.

Environment: - Frontend (react) and backend run on the same machine (loopback/localhost)—no cross-network scenario. - Firefox with active network.lna.blocking (experimental Local Network Access feature, Chromium’s equivalent is Private Network Access).

Root Cause (Analysis): 1. apps/react/sw.js registers a global fetch listener via Workbox and calls workbox.core.clientsClaim(). This causes every open page to be immediately controlled by the Service Worker. 2. registerServiceWorker() is called unconditionally on every app start, regardless of authentication state—even on the login/OIDC page. 3. The app uses hash-routing (URL fragments like “#/oidc”); the login page and the rest of the app share the same document URL, so you can’t restrict the SW scope to “everything except login.” 4. Once a page is Service-Worker-controlled, every fetch—including requests not explicitly handled by Workbox routes—first goes through the SW’s fetch event (default behavior when any fetch listener is registered) before proceeding to the network if it isn’t intercepted. 5. Hypothesis: Firefox’s LNA implementation doesn’t correctly inherit the address-space classification (loopback/private/public) for SW-forwarded requests across the controlling client. A direct document fetch (loopback→loopback) is allowed, but an identical target fetch routed through the SW is blocked.

Reproduction (minimal): 1. Use Firefox with network.lna.blocking=true (the default in affected versions). 2. Load a page that registers a Service Worker with a fetch-event listener (e.g. via Workbox precacheAndRoute + clientsClaim()). 3. Ensure both the page and the target resource are served from localhost/loopback. 4. From the SW-controlled page, call fetch() against the loopback target resource → the request is blocked. 5. By comparison, the same fetch from a non-SW-controlled page succeeds. 6. Setting network.lna.blocking=false also allows the fetch to succeed under SW control.

Excluded Causes: - Different address spaces for frontend/backend (both are on the same loopback machine)—ruled out. - Misclassification due to redirect_uri or cross-origin navigation—the OIDC redirect is a top-level navigation (unaffected); only the subsequent backend call (token exchange/session validation in SsoLogin.tsx → ssoLoginSubmit) fails.

I can't open, delete, uninstall or update my Firefox on my laptop???

I dont have much Ram space on my computer - but am working on expanding it.

Yet, still - I can't open, delete, uninstall or update my Firefox on my laptop

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've had a problem for a while where Firefox tells me "Firefox is being updated by another instance" and the only way I've been able to get updates is by using the installer.

In my attempts to resolve this, I learned of the `about:profiles`. I have never set up profiles so I figures I should only have the 1 default profile but it turns out I have `default`, `default-release`, default-release-1`, and `default-release-2`.

Of these profiles, the `default-release` is the 1 that has my data while it is `default-release-1` that is able to update.

I would like to make it so that I only have 1 profile that has all of my data AND is able to update.

I already tried removing all the profiles accept the one with my data but that leaves Firefox unable to update. I restored all the profiles I removed and I am back to where I started.

Does anyone have any suggestions?

Hello,

Ever since latest update (153.0 (64 bits) everything crash. I can open Firefox, but as soon as I enter a website, regardless of what it is, it won't load.

If i try to close the app, there's always a process that keeps running. It can't close. And if I try to force it it says that access is refused.

After that I keep receiving these errors that Firefox is already open and I need to close the last process of Firefox to continue but even if I say to close, it keeps repeating until my PC finally crash.

Everything was working 100% until Firefox updated itself. No Windows update nothing.

I can't even send crash report since it does the same error.

Multiple attempts to open Firefox produced a popup window indicating that "platform version 153.0 is not compatible with min version 152.0.6 max version 152.0.6 Maybe try to reinstall Firefox." If this is the only solution, how do I do this and retain my bookmarks, themes, etc profile? Thank you.

Julian H. Ethridge julesrdot27@frontier.com

So I just upgraded my pc and it bricked my windows and to reinstall, I forgot to save the Firefox data before doing so because I thought it wouldn't cause any issue, well, now all my bookmarks etc. are gone and I'm wondering if there is some sort of backup somewhere saved by Mozilla in the cloud.

My Firefox account data seem to have ben ALL deleted after a regular computer restart. There are no backups in the Firefox profile folder either. Years worth of passwords, bookmarks, tabs ALL GONE. After computer restart, when I was restarting Firefox, I vaguely remember a prompt on the screen that Firefox servers don't contain any data for my profile anymore. How could this have been brought on by a computer restart though?Any ideas what is the problem here, and how to recover my profile data? Any suggestions will be much appreciated.