Diễn đàn hỗ trợ Firefox

My firefox has been acting weird all of a sudden. Usually when I open firefox it loads all my tabs of the previous session and prompts me to enter my master password. But now when I start firefox, it opens for a brief moment and then instantly closes again. When I open firefox again all I get is a new empty window without any tabs, the password prompt also doesn't appear. So I have to manually open my last closed window to get the old window with all the tabs back (so I guess the window that closes instantly was the proper one) but the master password prompt won't show up. I can't access all my saved passwords in the password manager since I'm expected to sign in but when I click on "sign in" nothing happens - I guess the master password dialog just doesn't show up blocking me out of it. The only solution I have found so far is to go to about:support and clear start-up cache data. When it reopens afterwards I get the working window back, with my saved tabs and the master password dialog shows up - everything works. But it only works for this session, when I reboot the computer I have to do the whole issue again. Opening it in safe-mode also works but I need my addons and since it starts after clearing startup cache I don't think the addons are to blame. It just happened all of a sudden, I didn't install any updates or new version prior to the error.

Can anyone please help me? :(

my tabs bar, containing several hundred tabs, in firefox has suddenly decided to disappear and i can't get it to show. same for the menu toolbar (the one w/ the open, save,...) never really know which toolbar i am looking for. using latest version of ff and windows 11 desktop tried to get info directly from mozilla, but is the only place that probably has the answer.

what ever happened to support for the browser? it was relatively easy to get to the support area but now it mostly shows self-advertising for firefox.

thanks in advance for any help on this matter!

wolfgang

I've received notifications from Mozilla stating my Mozilla account was used to sign in. Info posted in email states it was Firefox on Windows 10. My city and state accurate. Day, date, and time is ok. I've been using windows 11 for some time now. How can i trust Mozilla, if they can not detect the right windows version?

Thanks. George K

Hello Mozilla Support Community,

We are troubleshooting a cross-origin resource sharing (CORS) issue specifically occurring in recent Firefox releases when processing custom B2B appointment requests.

Setup & Context:

Our production application, Frontline Sales Consultancy (flsc.co.uk), triggers a client-side fetch request to an external CRM gateway.

The request works seamlessly on Chrome and Edge, but Firefox throws an NS_ERROR_DOM_BAD_URI during the OPTIONS preflight check.

Observed Behavior:

Firefox Web Developer Console shows the preflight request failing before headers are evaluated.

Access-Control-Allow-Origin and Access-Control-Allow-Methods are explicitly declared on our origin server.

Does Firefox handle strict MIME-type checking or preflight caching differently for custom HTTPS API endpoints?

Any insights into Firefox-specific CORS strictness or network console debugging flags would be greatly appreciated.

Thanks!

Suddenly, I am getting unwanted ads every time I do a search or open another window on Firefox. It is extremely annoying and I have tried everything. This annoying practice includes even opening opinions/articles in the wsj. This, I believe, is outside what a browser should be providing. Popups that are unwanted and are part of the operating system is just not right. I am considering going to another browser as my default because of this intrusion.

FF 154.0 will not create a backup file. Trying to create an initial backup to my D: drive (2 TB Samsung 990 Pro M.2 Gen 4 NVMe SSD with 86% free space). WIN Pro 25H2 Operating system, Intel Core i7-14700K CPU; 64 GB DDR5 - 5600 MHz Corsair Vengeance DRAM.

No matter what I do I can't get the initial backup to complete even though the D:/Restore Firefox folder was created. I consistently get this message, “Hmm, there was a problem with the backup. Please try again in a few minutes.” The message result of browser.backup.backup-debug-info is:

{"lastBackupAttempt":1787153673,"errorCode":9,"lastRunStep":13}

Hello, I am writing to report a critical flaw in the new Firefox Local Backup mechanism (HTML-based container). After formatting my PC and installing a fresh copy of Windows 10/11, I attempted to restore my 10 years of browser history using a valid backup file (.html, ~102 MB) created by Firefox 153.0.4.

Although the password was correct (the UI immediately rejected incorrect ones), the restore process completely failed and entered a destructive loop. Instead of extracting the data, Firefox started infinitely creating hundreds of empty profile folders in %AppData%\Roaming\Mozilla\Firefox\Profiles without throwing a visible error to the user, completely messing up the profiles.ini file.

What had to be done to recover the data: Since standard unarchivers (7-Zip) and tools like Windows certutil couldn’t parse the hybrid HTML/Base64 container, we had to reverse-engineer the recovery process using the internal Firefox source modules (PreferencesBackupResource.sys.mjs and SessionStoreBackupResource.sys.mjs from omni.ja).

We had to write a custom Node.js script to:

1. 1 Parse the specific block-by-block Base64 encoding used by Mozilla inside the HTML wrapper.
2. 2 Manually decrypt the raw binary data using the backup password.
3. 3 Extract places.sqlite, logins.json, key4.db, and sessionstore.jsonlz4 manually.
4. 4 Manually inject these files into a freshly registered profile.

The Bug Core: The built-in extractor in Firefox fails on fresh OS/browser installations due to path/profile synchronization errors, causing a crash loop that generates endless ghost profiles.

Please review the block-by-block extraction logic and add strict exception handling to the Local Backup UI so it doesn't break the profile directory when a routine error occurs.

Thank you.

I believe I got an automatic update to Version 154.0 yesterday on my Windows 11 laptop. When I opened Firefox after the update I got stuck

My Bookmarks appear to still be available, but my passwords are gone. The passwords are still available on my iPhone and iPad

I have tried syncing to no avail.

I need my passwords. How can I get them back?

I am experiencing a severe issue on the LINE Official Account web app (https://chat.line.biz) using Firefox.

Problem Details: 1. Every time I switch between customer chats or type a reply, the chat window automatically jumps/scrolls up to old messages (sometimes minutes prior) instead of staying at the latest message. 2. It happens consistently across almost all chat threads, forcing me to manually scroll down every single time.

Troubleshooting already attempted: - Cleared all Cache, Cookies, Local Storage, and Session Storage. - Tested in Troubleshoot Mode (all extensions disabled). - Toggled layout.css.scroll-anchoring and general.smoothScroll in about:config. - Issue does NOT occur on Chromium-based browsers (Chrome/Edge).

This seems to be a compatibility issue between Firefox's DOM re-rendering/scroll anchoring mechanism and LINE OA's React web app code. Please help investigate.

I got a notice that an upgrade was available. I choose it and it wiped out all my bookmarks, my bookmark bar and all. Nothing works to recover, I tired going to previous version. That did not restore my system. I will quit using your product forever if you do not restore my settings.

I am frustrated by your constantly asking for my password and in the process your site is just a maze in which nothing is defined in getting a new password in the place of the old one I forgot....

Hello.

Has the profile logic been thought through?

When I set a default profile, I would expect

A) all new pages open into the default B) That firefox always opens the default without request.

This does not happen.

firefox.exe -P is set correctly.

Any ideas? I feel after the profile choice was improved, the basic logic may of been broken.

Thanks

Playback works correctly usually, but if I jump forward or backwards in time it sometimes never loads. This also completely bricks the whole brower, all other tabs etc, until I close firefox and restart it. This happens on all vods of twitch, and also livestreams where I am able to rewind (subscriber function). I have no extensions enabled, and have the default settings on firefox etc. ("Use recommended performance settings") Video of it happening: https://www.youtube.com/watch?v=3difRLhE-cA