I-Firefox Community Forum

Hi Mozilla Support Team,

I am experiencing severe browser lag and high CPU usage on Firefox specifically when managing complex backend forms and inventory management scripts on our e-commerce operations portal.

The page script execution freezes when opening multiple tabs alongside developer console tools. I have already cleared cache and disabled third-party extensions, but memory leaks still happen during heavy DOM rendering.

Is there a specific setting in about:config or hardware acceleration flag recommended for heavy web app environments?

Thanks!

Firefox hangs when Thunderbird is open. At this moment, Thunderbird is not open and Firefox is hanging on opening any web page. I had to use Chrome to get to this site and request help. Here is info about my PC:

Device Name Ginny-PC Processor Intel(R) Core(TM) i5-4430 CPU @ 3.00GHz 3.00 GHz Installed RAM 8.00 GB (7.88 GB usable) Storage 233 GB HDD Hitachi HDP725025GLA380, 466 GB HDD ST500DM002-1BD142 Graphics Card Intel(R) HD Graphics 4600 (113 MB) Device ID 13E09BB5-804A-4882-A64D-CA16EABC9EF4 Product ID 00330-80000-00000-AA914 System Type 64-bit operating system, x64-based processor Pen and touch No pen or touch input is available for this display

Edition Windows 10 Pro Version 22H2 Installed on 9/8/2020 OS Build 19045.6466

Since the last update 155.01 I can't use Firefox as it freezes and hangs after 3 - 10 seconds. On Windows 10 , 64 bit. There seems a bug with the last update for Windows 10 users

Crash report: https://crash-stats.mozilla.org/report/index/c0455e29-69e9-4030-8b03-fdf430260909

Not sure the crash report is related to the issue.

The same issue happens to all of my 3 Windows 10 PCs since the update from today.

I have uninstalled Firefox and downloaded again, but same issue happens again.

I cleared the cache also but to no avail

How can I use Firefox again?

When I use Firefox, everything feels slow. Videos pause and stutter often. Pages take a long time to load. I have cleared cache and restarted the phone but it is still happening. Please help me fix this so it works properly again."

This morning, I can no longer download (Save) files to my computer, nor check/change settings in Firefox. Tried all troubleshooting steps to no avail.

If I delete and reinstall Firefox, will I lose all my Bookmarks, etc.? Running version 157.0 (aarch64).

Appreciate any help!

So I know these websites are kind of crap anyway, but I have issues with scrolling bsky.social (and other clients for it like witchsky) and twitter. The further into the timeline I get, the more frequently these webpages lag.

They begin freezing every few seconds for a few seconds, during which they queue left or right clicks, page up/page down, and various other commands, only processing them once it unfreezes. Firefox itself still works during this freeze, e.g. opening the main menu. Also, I can still scroll up or down to a limited degree, though this just exposes empty, unrendered webpage until it unfreezes.

bsky.social has had this problem for a long time, but twitter only recently developed this issue after I had to do a cache clear, cookie clear, etc. trying to log in a few weeks ago. Prior to that it didn't have this issue.

Task manager hasn't really helped elucidate what's wrong, so it might be an about:config that I set or even an unruly extension, but I really don't know what to try.

When I use Firefox, everything feels slow. Videos pause and stutter often. Pages take a long time to load. I have cleared cache and restarted the phone but it is still happening. Please help me fix this so it works properly again."

Hi,

Whenever I try to upload any sort of file, the file explorer pop up thing opens, and then freezes. This doesn't happen with any other application, just Firefox, and it happens across websites. Eventually the window freezes long enough that you get the 'close/wait to respond option', and then it closes. Firefox itself doesn't freeze, just the file picker. Nothing ever crashes/closes unexpectedly, and there's no crash reports in the about:crashes thing.

It's not super urgent because you can copy and paste most files but it is frustrating. Any help would be very appreciated.

Thank you

Everytime I switch app and come back to the browser, my tab reloads. So like if I am watching a youtube video and I've watched it almost half, after the reload it starts over.

I've uBlock origin and Hide Shorts extension installed.

The new Firefox 157.0 update has broken pretty much every video streaming website. I've tried YouTube, Twitch, and Amazon Prime Video. In all cases, the same thing generally happens.

Take YouTube for example. The main page itself is slow to load. And when I click on a video to play, it either fails to load or loads but has horrible stutter. When I open up the Firefox Task Manager, every YouTube page shows it's using 100% CPU.

I've enjoyed using Firefox for years, but I'll be moving on to different browser now.

Ever since the update to 157 I have been having issues when running firefox. Youtube is non functional on the browser. It is using a large amount of memory (consistently at 41-45% according to the task manager). Gmail takes a long time to load, in fact every page takes a long time to load if at all.

I run it in troubleshooting mode and functionality returns... I don't want to run firefox with all my extensions disabled they are there for a reason.

This update seems to be inherently unstable and is causing issues for lot's of folks.

So just to summarize, the update to 157 has not worked. It is using a disproportional amount of memory, that the previous version did not. It is causing my entire system to downgrade and run significantly slower. Pages will not load properly and I am now using a different browser as a work around.

Essentially it is a huge failure and I wish you would have tested more thoroughly. My experiences are not uncommon... You guys released a garbage upgrade to the browser that has catastrophically under performed.

I do not recollect any update in the past that functioned as poorly as this. Congratulations for completely screwing this up.

When will you guys get this working properly?

Dear Mozilla Firefox Support Team,

I have been a loyal Firefox user for many years because I have always appreciated its speed, privacy, and reliability. However, I have noticed that Firefox has become slower over time, and I am disappointed with its current performance.

The browser feels increasingly sluggish during everyday use. One of the biggest issues I experience is with YouTube, where videos often do not play as smoothly as they should. I also notice that Firefox consumes a significant amount of RAM, even when only a few tabs are open, which affects the overall performance of my computer.

I sincerely hope the Firefox team will prioritize performance optimization in upcoming updates. Many users, including me, want a browser that is fast, lightweight, responsive, and efficient with system resources. Speed and smooth performance are some of the main reasons people choose a browser, and I would love to see Firefox become the quickest browser again.

Please continue improving memory management, reduce unnecessary resource usage, and optimize YouTube and other modern websites for a smoother browsing experience.

Thank you for your hard work and for listening to user feedback. I hope future releases will focus on making Firefox faster, lighter, and more responsive.

Well I am continuing and repeating my question placed in August 2026, where I found that Firefox V154.x stalled in an erratic way that made it completely impossible to use it or to send a crash report. So your suggestion to send a crash report was not very bright or helpful. I deliberately omitted the subsequent updates, to try again after a main version update. Alas, we have the same situation again in V157.0, this time more predictible. The program stalls immediately after trying to open another tab. And again, you can kill the program only by task manager.

The additional question I have, is how to switch off the annoying update message, as long as Firefox is dysfunctional after an update, I'd like to avoid any update under all circumstances. I have to work with Firefox, so it is more than an leisure thing for me, I cannot afford to cripple Firefox by an unintended update.

I had to reinstall the last known working version (153.03) to send this message.