Firefox Community Forum

For the past 15-16 days, Firefox has been consuming extremely high memory.

The problem: - When Firefox first opens, it starts normally at around 300-400 MB - But after using it for about 1 hour, a single Firefox window grows to 1-2 GB of RAM - This keeps increasing the longer I use it (memory leak behavior) - Currently Firefox (41 processes) is using over 5,131 MB total memory on my system it's normal but after 1 hour a single firefox window grows to 1-2 GB of RAM

What I have tried: - The issue happens consistently every day for the past 15-16 days - Other browsers like Chrome and Chromium use much less memory in comparison

System info: - OS: Windows 11 - Firefox version: latest version 148.0.0.0

Please help me fix this memory leak issue. It is making my system very slow.

Initually I was having issues where I couldn't get the print menu to load up (forever stuck trying to load the preview), however since then it has progressed to downloads refusing to download and the hamburger menu in the menu bar doesn't react when left clicked at all.

In Firefox's Task Manager, how do I know which tab is using which subframe(s) process?

For example, let's say I open Firefox and with only one single tab open, I open the following web page: https://audioplugin.deals/product/best-of-zampler-collection/

That page apparently includes content from several third-party websites because when I open it, Firefox's Task Manger shows processes for the following:

https://audioplugin.deals https://cloudflare.com https://google.com https://hcaptcha.com https://soundcloud.com https://stripe.com https://stripe.network https://stripecdn.com

The process for "https://audioplugin.deals" is the only process with a tab. All of the other processes are subframe(s) only, with no mention of which tab is using them.

With only one tab open, I intuitively know that all of these processes must be used by that one tab. But like most people, I browse using multiple tabs, and once you open multiple tabs, it becomes (as far as I can tell) impossible to determine which subframe(s) process is used by which tab. This makes it impossible to determine which tab is behaving improperly or erratically when there are issues (for example, when one of those subframe(s) processes is consuming an unreasonably large amount of memory or CPU cycles).

I am just an average end user and want to alert you to my problems and would love a solution. I am sorry that I don't have the kind of specificity in the details which might help (I am too busy doing other things and when firefox becomes too much of a pain, I generally close it and switch to another browser). I am providing my general observations. On my updated windows 10 64 bit system, firefox v148 seems to have made the browser unusable for me. Other browsers do not suffer similarly (Chrome, Edge, Opera, duckduckgo). I have had these types of issues with Firefox in the past, but they resolved with prior updates. I am at the point of switching to another browser - I hate the thought of it, but Chrome seems to be the most stable and functional. Symptoms:

• Firefox browser and the computer gradually become slower as firefox starts hogging cpu and memory and starts using a lot of power
• extensions stop working - eg, Keeper extension stops filling fields or fills incorrectly, Malwarebytes extension seems less responsive, running background sounds makes things even worse (https://www.mynoise.net/) and web pages with continuous updates (eg, map.purpleair.com) stop working altogether
• other pages stop loading, load with errors ('bad connection') or load very slowly, especially, but not always, those with more security, eg, my bank or retirement funds sites.
• after i close Firefox and start fresh, symptoms resolve, then rinse and repeat.

The previous version worked great and seemed to solve similar issues I have had with earlier releases. I assume the last stable release for me was one of the 147 versions. but when things are going well (which is most of the time), I'm not watching closely, or at all.

Second time asking for help: Firefox "hangs" for 30-60 seconds the first time I open it on my MacBook Pro. Am running Firefox 148.0 (aarch64) on Mac OS Tahoe 26.3.1. This has been going on for three months. Have tried uninstalling Firefox and using AppZap to erase my Mozilla profile from the Mac -- rebooting the Mac -- and re-downloading a fresh copy of Firefox. I shut the Mac down for about an hour, rebooted, and Firefox launched right away. But the next time I launched Firefox on reboot, it "hung" again. Spinning beach ball for about 45 seconds before it then opened its default page at open. I do not run a VPN, and disabled some Safe Browsing "features" of Intego Virus Barrier.I tried to eliminate any other third-party extensions from my Firefox that might cause the delay. Am attaching an image of the extensions Firefox currently uses on the Mac. I absolutely <loathe> Safari, but can't have my Mac use Firefox as a default browser if it "hangs" on first launch. One last thing. Early on in the process, I tried deleting my Mozilla Firefox User Profile, but Firefox refused to start because it couldn't find a profile to launch with. So did not go there on this last attemt. Thanks in advance.

I have around 60 tabs open accross 5 windows, and whenever I try to open a new tab, Firefox takes many minutes to load completely. I've restarted Firefox and the problem is solved for a few days, and then it persists. I've been using Google, but I want to keep using Firefox. Fix it now please.

I'm elderly,so bear with me. Firefox very often slips off the screen or simply vanishes.Often it disappears to a thin,gray line at the bottom. Can't open a document and have Firefox available,too. I'm 84....are my fingers worn out? Dave P.

If I am on a website that is still loading in Firefox and want to change to another URL, then Firefox does not stop loading the old page. Once I click the "X", then it loads the new URL webpage. Shouldn't it stop getting data from the old URL the instant I load a new URL?

在 Firefox 内部：

通过 JS 触发的新页面 通过 a.click 触发的新页面 甚至 rel=noopener 都会被标记为：

“related browsing context”

进而共享同一个进程，新页签因为内存占用过高，导致旧页签卡死。

通过设置

1. 添加 COOP 响应头 add_header Cross-Origin-Opener-Policy "same-origin" always;也无法解决

设置空白页再重定向也无法解决

I love Firefox and NEVER use Safari. I thought something had happened to my MacBook Air, stuck space bar or maybe even a virus? BUT the space bar issue doesn't occur when I use Safari. The issue is this: I will use Firefox (for everything). All of a sudden, the space bar becomes "engaged" and my text starts scooting across with spaces between it. I can hear it "stutter" a sharp sound each time it lurches along. I can then open up a word doc and the thing follows me there. Or when trying to close an unsaved word doc to prep for closing the computer. I restart the computer and to begin with, the spacebar issue is resolved but before long (sooner and sooner) it begins again to the point that I am restarting my computer now within about five minutes. I have uninstalled and re-installed Firefox to no avail. BUT, I can use other programs without problem as long as the problem hasn't already begun again, via Firefox. What on earth? I am now stuck using Safari... I have the most recent Firefox installed. I just re-installed the program a second time, yesterday. I don't want to open the program or I'll end up turning it off and on again and lose all of this but it was updated as of yesterday but I keep up on all the updates, all the time. It's been going on...about 4 weeks? But it started with occurring maybe once a week, then once a couple days now to the place it is multiple times to constant, during a day. I cannot use Firefox until this is resolved. Thank you for whatever help you can offer. I've run the diagnostic /first aid stuff to no avail through my utilities.

Hi, for about the last week (23 Feb 2026) when watching videos in my Firefox Browser, there are short stutters. First noticed in Youtube, so looked for updates to UBO and other extensions. Then noticed the same thing in BBC iPlayer and my4 streaming. It also happens when watching my media via Plex in the browser. It is not my network bandwidth or speed.

When I watch media via my Plex app or videos on VLC media player, there is no stutter.

I have included a link to logs recorded in Firefox profiler as suggested by someone on Reddit. firefox_profiler_2March26 https://share.firefox.dev/4b4moC0

I don't know if this is caused by a Firefox update, a Windows update. Laptop: Asus ROG Flow X16 (2023); Intel i9-13900H, Intel Irix Xe; NVIDIA RTX 4070 (mobile) Firefox 148.0 (64bit)

All drivers up-to-date. Please let me know if the link does not work - my first time trying to upload a link from profiler.

Thanks all.

I've noticed in the last few days that I'm periodically losing keyboard character input on sites following the update to the latest version - 148.0 (64-bit) I thought it might be a power issue with my WiFi keyboard and swapped out the batteries but the issue has persisted and I haven't experienced it when testing in Edge and nor have I seen it when using Excel or Notepad++ which I use regularly. Keyboard input actually froze for 4-5 seconds in inputting the last sentence. The problem is presenting on a number of sites - e.g. Reddit and YouTube. I do use the Ublock Origin extension but have been doing so for quite some time. I did report an issue with the mid screen search bar a few days ago and believe that is to be corrected in the update of 10th March. Is this also a known issue with the update?

warum ist die obere zeile mit dem kreuz beim start nicht mehr da? Sieh die markierung im Bild! immer wenn ich firefox starte mus ich es erst nochmal minimieren und dann wieder öffnen. was soll der scheiss

und Könntet ihr eure hilfe auch mal auf deutsch machen dann könnte mann wenigstens was lesen ode alles extra übersetzen zu müssen