Firefox Community Forum

I am using Firefox on Linux Ubuntu 26.04. I normally work with multiple tabs. Then I quit Firefox with all tabs open at the point of quitting. Some times on the rare occasion there can be a forced quit due to some issues. In my settings I have configured it not to open the previous tabs. In fact I want a blank page. But whenever I reopen Firefox, it opens those tabs and tries to reload which is annoying. Some of these pages take a long time to reload, and why would I want to look at tabs which I already have read. Or if it crashes due to some website on a tab why reopen something that crashed in the place ? Can you fix this. Thanks.

On Arch Linux with the latest version of Firefox, the interface elements turn black due to a theme loading failure. 'This issue persists even when using the default theme.

Going to Settings and disabling the theme (which automatically falls back to another theme) resolves the problem.Re‑enabling the problematic theme does not reproduce it immediately. However, the issue reappears after restarting Firefox.

System Info: OS Arch Linux x86_64

├   KER  Linux 7.1.3-arch1-2
├   PAK  1537
├   AGE  34 days
└   USR  chen-shuhan@archlinux

WM niri 26.04 (Wayland)

├   SHE  fish 4.8.0
├   TER  kitty 0.47.4
└   TFO  JetBrainsMapleMono-Regular (13.5pt)

Hello. I am back again with the same issue that I presented on the forum post three months ago. https://support.mozilla.org/en-US/questions/1594903?utm_campaign=questions-reply The difference is now it is happening on Firefox v157.0.1;everything else is identical. Qubes os R4.3.2 with Firefox 157.0.1 in a Fedora 44 xfce VM. To recap I open one window for Proxmox Datacenter Manager and as soon as I click to sign in Firefox completely disappears. I can open this in Chromium browser and Firefox ESR v.140.17.0 esr perfectly fine. Please consult the original post for all I did to troubleshoot this. I am working with the esr version now but would like to help put this issue to bed. Community members stepped up last time to help me so I am here to do my small part for others. Ask for any info you need and I'll reply ASAP. Thanks in advance. SDS

Ubuntu - I use the SNAP version of Firefox - I generally have lots of tabs open but only use 5 or so of them and it's generally fine.... but when I am closing Firefox, it USES like 100% of the CPU and ALL of the RAM and ALL of the SWAP memory when closing.

This locks up the computer.

Sometimes it doesn't quite go all the way but I can watch it all happen in real time, using Task Manager - and that shows a solidwall of all resources occouring, when the close Firefox is run.

I am told by research via ChatGPT that this is a very real problem with the SNAP version and it's best to change to the Debian version, copy all the bookmarks etc., across and then uninstall the SNAP version.

It's rather disconcerting to have Linux crash because of this one app locking it up and frequently.

Chat GPT:

Is there a problem with Firefox Snap Version closing and using all the resources while doing so, which results in locking up the computer?

You're definitely not imagining it—there have been reports of Firefox's Snap version consuming excessive system resources (CPU, memory) and even causing lockups or hangs, particularly during closure. Here's what’s going on and how to mitigate it:

What’s Happening with Firefox Snap?

2. Browser Hangs or Locks the System on Close

On Linux (especially Ubuntu), users have reported that closing Firefox can lead to it hanging in memory, sometimes unresponsive and still consuming resources.
Super User
Ask Ubuntu
A stark example from Reddit illustrates the severity:
“About 50% of the time I open Firefox, it'll reach 100% CPU usage in about 30 seconds… PC completely unusable unless I shutdown.”
Reddit

3. Known Wayland Sway Bug

On Wayland/Sway setups, reloading Sway while Firefox is open can trigger intense logging, causing high CPU use and an enormous syslog.
Fix: Set MOZ_DISABLE_WAYLAND_PROXY=1, or upgrade to FF 125 where the issue is addressed.
Reddit+1

Alternative Approach

Many users, particularly on Ubuntu, opt out of Snap completely in favor of the .deb package or PPA builds. These alternatives often avoid these specific issues. Ask Ubuntu Reddit

Thoughts? Solutions?

Thanks in advance.

Firefuxxed was refusing to open new tabs so I shut it down and restarted it (always fixes it) and all my pinned and open tabs were gone with no way to recover them, it took me half an hour to manually restore the pinned ones one by one but not all of them as I cannot remember all of them let alone all the open tabs I had (hours of research gone down the toilet).

There should be a way to backup and restore pinned and open tabs so this doesn't happen, the history option does nothing.

OS: Linux Mint 22 fresh install from a week ago Previous version of Firefuxxed updated after this shamossel.

Hello, For about two or three days now, when I launch Firefox and try to open any website, it takes maybe one minute to load the page, then the navigation is OK on every website.

It only happens when I launch Firefox for the first time of my session. If I close it then relaunch it, it's still very swift.

I tried clear cache and remove cookies, just lost my logins lol but didn't work. I also tried with no extensions, nothing changed. Lastly I tried to set "network.captive-portal-service.enabled" to "false" in "about:config" but it didn't change anything neither.

So before I try anything else that could erase something on my profile, I'd rather ask here for some help :)

PS: running FF 153.0.4 on Debian Trixie with Mozilla repos. Only have two extensions: µblockOrigin and NoScript.

Thank you in advance!

After connecting and signing in to Mozilla Connect, it seems impossible to actually log out. There is a log out option in the dropdown menu, but it doesn't work. After "logging out", when going back to the site one is automatically logged back in. This is true even after clearing all mozilla.org cookies, and closing the browser. If a different browser is used, first time access to the Mozilla Connect site requires username/email and password, but after the first access, the alternate browser is also perpetually logged in.

1. What mechanism is being used to identify me as the user after cookies are cleared ?

2. How does this fit in with Mozilla's claims to respecting user privacy ?

3. How do a log out of the Mozilla Connect site ?

I am experiencing an issue where Google.com (other google domains work fine) will not load in Firefox, resulting in an infinite loading loop. Other browsers on the same system (Brave) work fine.

Here are the steps I have already tried:

Reinstalled Firefox completely

Removed Firefox via sudo apt remove --purge firefox -y

Cleared all user profiles and caches: ~/.mozilla/firefox, ~/.cache/mozilla, ~/.config/Mozilla

Reinstalled via Flatpak

Tested network connectivity outside Firefox

curl google.com works correctly

DNS resolution works via getent hosts google.com in the host system

Checked proxy settings

Ensured “No proxy” is selected in Firefox → did not resolve the issue

Tested in Safe Mode (disabling extensions)

Problem persists, so not caused by extensions

Tried disabling IPv6 inside Firefox

network.dns.disableIPv6 set to true → no effect

Cleared DNS cache inside Firefox

about:networking#dns → clicked “Clear DNS Cache” → no effect

Disabled DNS-over-HTTPS (Secure DNS)

about:preferences#privacy → “Use secure DNS” → disabled → no effect

Disabled HTTP/3 (QUIC)

network.http.http3.enabled set to false → no effect

Verified Flatpak network permissions

flatpak info --show-permissions org.mozilla.firefox shows network access allowed

Inside the Flatpak shell:

flatpak run --command=sh org.mozilla.firefox getent hosts google.com

→ returns only IPv6 address: 2800:3f0:4001:839::200e google.com

Please forgive me if this question was already answered and that I might have accidentally overlooked that answer.

I'm running Firefox 144.0 (64-bit) under Debian 13 (linux).

I want to configure Firefox to never restore any previous session when it starts up, irrespective of how Firefox was last exited.

Even if a running Firefox session was externally killed via some sort of system command or because of a reboot, I never, never, never, never, never, never, never, NEVER (!!!) want it to restart in any previous session.

I ALWAYS (!!!) want Firefox to launch with its default start page, no matter what.

I tried all of the suggestions that I have found on line about how this might be accomplished, but with each one of them, there are cases where the previous session was restored.

I repeat, I do NOT (!!!) EVER (!!!) want the previous session to be restored, under any circumstances.

Is there a way to accomplish this?

Thank you in advance for any suggestions, and again, please accept my apology if this has been answered and I overlooked that answer.

Hi,

I discovered today that the installation of Firefox I have has modified some emoji, like the flag of Switzerland has been replaced with the one from Sark. See the screenshot looking at the same website with Firefox on the left, and Brave on the right:

There's a big mess in the flags' emojis apparently looking at a page showing all the countries. See second screenshot.

Well, I am in a real mess. Three days ago I lost the ability to access my favourite website. I CAN access the website in the Brave browser. The website owner has told me that it is not a problem with my account with them so it must be a Firefox issue. Before this happened I had been trying to move and delete files on my laptop and have got very confused about EVERYTHING. In that I had deleted my Firefox recovery folder(s). I have managed to move them back into my Home folder before they expire. Now I am being asked to enter my "password" to initiate the restore. But the several Firefox passwords in my laptop are not being accepted. How can I get a new password? If that is not possible do I have to delete my Firefox account? What is my best way to recover from this mess? Any advice is greatly appreciated.

I can't access the keyboard hotkeys config page as instructed in https://support.mozilla.org/en-US/kb/customize-keyboard-shortcuts-firefox. Typing about:keyboard into the address bar gives an Invalid URL error, as seen in the attached screenshot. I am able to access other about: pages.

https://apollolaunchcontrol.com/v20test/http___www.apollolaunchcontrol.com_/Crawler_Transporter.html

There's three images on the page, in FF only the top one shows, but if I hit refresh, all three show, but only for half a second, then they wink out. All three show in Chromium just fine.

140.16esr under Debian 12.

I don't know if this ever worked in FF, since I've been on Chrome a while. I tried canvas.toBlob() in FF without a solution.

The behavior is the same whether the served image is jpg or webp. A Servlet delivers the image data, here in webp:

          response.setHeader("Content-Type", "image/webp");

On page, I use a canvas thus => see '// FIREFOX'

     var canvas = document.createElement( 'canvas' );
     canvas.width = width;
     canvas.height = avail_height;
     var context = canvas.getContext( '2d' );
     context.drawImage( imgsrc, 0, 0, width, avail_height);
     context.lineWidth = 150;

     // FIREFOX: canvas.toDataURL('image/jpeg')=black, png,webp,default=transparent
     img.src = canvas.toDataURL('image/jpeg');

     img.onmousedown = disableDragging; // for FF
     img.style.opacity = "1.0";
     console.log('setImg ok');

Inspecting a black jpeg:

        data:image/jpeg;base64,...

Thanks!

Hi There are image display issues with Firefox. The attached image shows a screenshot comparing the same page on Glazy.org: Chrome on the left and Firefox on the right. The image appears too dark in Firefox, making it difficult to work using that browser. Is this a bug or a setting that needs adjusting? I haven't been able to find a solution. Thanks for your help.

hi,

  I have an old PC with this CPU:

Architecture: i686

 CPU op-mode(s):         32-bit
 Address sizes:          34 bits physical, 32 bits virtual
 Byte Order:             Little Endian

CPU(s): 1

 On-line CPU(s) list:    0

Vendor ID: AuthenticAMD

 BIOS Vendor ID:         AMD                                             
 Model name:             AMD Sempron(tm) 2400+
   BIOS Model name:      AMD Sempron(tm) 2400+                             CPU @ 1.6GHz
   BIOS CPU family:      29
   CPU family:           6
   Model:                8
   Thread(s) per core:   1
   Core(s) per socket:   1
   Socket(s):            1
   Stepping:             1
   BogoMIPS:             3333.66
   Flags:                fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat p
                         se36 mmx fxsr sse syscall mp mmxext 3dnowext 3dnow cpuid 3dnowprefe
                         tch vmmcall

Caches (sum of all):

 L1d:                    64 KiB (1 instance)
 L1i:                    64 KiB (1 instance)
 L2:                     256 KiB (1 instance)

Vulnerabilities:

 Gather data sampling:   Not affected
 Itlb multihit:          Not affected
 L1tf:                   Not affected
 Mds:                    Not affected
 Meltdown:               Not affected
 Mmio stale data:        Not affected
 Reg file data sampling: Not affected
 Retbleed:               Not affected
 Spec rstack overflow:   Not affected
 Spec store bypass:      Vulnerable
 Spectre v1:             Mitigation; usercopy/swapgs barriers and __user pointer sanitizatio
                         n
 Spectre v2:             Mitigation; Retpolines; STIBP disabled; RSB filling; PBRSB-eIBRS No
                         t affected; BHI Not affected
 Srbds:                  Not affected
 Tsx async abort:        Not affected

in some linux (arch 32 bit) I have problem executing firefox, Is there a version for CPU without request from SSE3 Flag?

thanks

I am the developer of FastF1, an open source Python package for downloading and analyzing Formula 1 race results, timing data and telemetry. The package is widely used in the fan community for independent analysis of results. For some advanced features, the addon requires users to authenticate with their Formula1/F1TV account. Since their services don't have an open login API, a companion addon is required to allow users to sign in using their browser and the official website.

I have just noticed that my developer account has been banned and the addon was blocked in Firefox. I have not received any email about this and don't know why exactly this decision was made. I'd like appeal this and reinstate my account and the addon, but I don't know how to proceed from here.

FastF1 and the companion addon are fully open source and intend no harm to users. https://github.com/theOehrly/Fast-F1 https://github.com/theOehrly/fastf1-companion

I hope this problem can be resolved.

I'm using Firefox from the official Ubuntu repository (packages.mozilla.org). I have used the (very cool) "translate page" feature successfully, but for some reason it doesn't seem to work on https://wiki.openstreetmap.org/wiki/NL:Basisregistratie_Adressen_en_Gebouwen which I'd like translated to English. Even though Firefox thinks the page was translated, only one of the headings seems to be in English.

I would like to understand how to troubleshoot this and help you improve this great feature. Thank you in advance.

Sometimes drag functionality stops working. I can't grab a tab to move it to another position or to a new window. (Holding left click on the tab and moving the cursor does nothing). Also, re-merging the tab with another firefox window stops working. (Dragging a tab to a firefox window from another firefox window doesn't merge them. It does nothing) I can right click on the tab and select Move to move it to a new window but dragging stops working. I have to close Firefox and start it again (sometimes twice), then dragging starts working again. This happens multiple times a day. I am on Linux Mint and the version is 126.0 (64-bit). This problematic behavior has only recently began.