Firefox takes all memory, crashes the system

Anixx · Apr 18, 2026

What can be the reason for Firefox taking all the memory?

It crashes my computer session pushing me to the logon screen several times a day by taking all the memory (of the 16GB total). It's the recently updated ESR version 140.9.1esr.

TairikuOkami · Apr 18, 2026

Memory cleaner? It is clearly a memory leak, either caused by hardware (BIOS) or software (driver, app, extension).

Tweak - Memory Tweak Downloads - Softpedia

Download software in the Memory Tweak category - Free Applications

www.softpedia.com

Cleanmem was literally designed for Firefox.

CleanMem Free/Pro

W

www.pcwintech.com

HeavyHemi · Apr 18, 2026

Anixx said:
What can be the reason for Firefox taking all the memory?

It crashes my computer session pushing me to the logon screen several times a day by taking all the memory (of the 16GB total). It's the recently updated ESR version 140.9.1esr.

View attachment 169209

Restarting Firefox doesn't release the memory?

KevTech · Apr 18, 2026

That is the problem with using ESR now as it is getting further and further behind the public release.

ESR is at 140.9.1 and public is now at 149.0.2

Kees · Apr 18, 2026

My bank did not accept the Firefox ESR version anymore, because it was 'too old'. Of course I could use a tricking 'agent' extension (I did for a while), to tell that site that I am using a newer version of FF. But it gives me more work to maintain the right version. So I decided to install the normal version.

My Firefox is using about 650 MByte when idle and about 800Mbyte to 1 Gbyte when I am browsing Elevenforum as only site in just one tab. But when I open a lot of sites, memory consumption is bigger. Opened 9 tabs and memory consumption (of Firefox only) is about 2 Gbyte in total.

zbook · Apr 18, 2026

There may be clues in the Windows log files.

Please run the V2 log collector > post share links

BSOD - Posting Instructions

BSOD - Posting Instructions This will show you how to help provide needed information about your system and dump files. It will not contain any personal or sensitive information about you or your data. To get better help with your Windows BSOD issue, please read these instructions and follow...

www.elevenforum.com

Add, Remove, and Change Display Language in Windows 10

How to Add or Remove Language Packs and Change Display Language in Windows 10

www.tenforums.com

Change Display Language in Windows 10

How to Change Display Language in Windows 10

www.tenforums.com

maur0 · Apr 18, 2026

Anixx said:
What can be the reason for Firefox taking all the memory?

It crashes my computer session pushing me to the logon screen several times a day by taking all the memory (of the 16GB total). It's the recently updated ESR version 140.9.1esr.

View attachment 169209

test this

Release r3dfox v150.0b10 for Vista+ · Eclipse-Community/r3dfox

Technically a beta, but I think it's stable enough in testing. Mostly wanted to get a release branded build rather than jumping into beta Plasmafox when fixing a major issue. Please read Hello, on...

github.com

cheaterslick · Apr 18, 2026

I'm using 140.9.1 ESR as we speak and have had no problem. But then, I'm also using the 32bit version which also caps out any memory loss.

Slavic · Apr 18, 2026

cheaterslick said:
I'm also using the 32bit version which also caps out any memory loss.

Right, 32-bit version technically cannot consume more than 4 Gb. If FF approaches this limit, it may crash itself, but not OS.
As for thread starter, I'd suggest to temporarily disable all extensions, clear cache and see the result. Similar way is to start FF in the safe mode:

Client Challenge

Josey Wales · Apr 18, 2026

I am using Fx 150 RC1 with no memory issues.

glasskuter · Apr 18, 2026

Disable all your installed FF extensions. If used ram drops to normal, suspect a corrupt or outdated extension. Enable one at a time. If usage is high with all extensions disabled, suspect corruption in FF.

Edwin · Apr 18, 2026

Anixx said:
What can be the reason for Firefox taking all the memory?

Type about: processes, (without the space), into the address bar and find out.

cheaterslick · Apr 18, 2026

Slavic said:
Right, 32-bit version technically cannot consume more than 4 Gb. If FF approaches this limit, it may crash itself, but not OS.
As for thread starter, I'd suggest to temporarily disable all extensions, clear cache and see the result. Similar way is to start FF in the safe mode:

Client Challenge

Last time it crashed was about a year ago. It got hung up on a certain webpage filled with beaucoup java scripts, so I'm not too concerned about it.

And I think there's some other issue with the OP's memory consumption. Malware, maybe?

One could save one's profile, uninstall FF with Revo, download the ESR 32bit version, install it and then import your profile back into it. Then see if the memory problem goes away or not.

cheaterslick · Apr 18, 2026

KevTech said:
That is the problem with using ESR now as it is getting further and further behind the public release.

ESR is at 140.9.1 and public is now at 149.0.2

It doesn't have all the bells & whistles of the regular release but the security updates with it are parallel with both versions. I don't get fooled by version numbers here.

It's very possible there's a FF bug involved, but do we know how widespread this is?

Edwin · Apr 18, 2026

Kind of a sh*tty rendering of the OP's Task Manager, but..., over 6 million KB of memory being hogged..., sumthin mighty suspicious goin on there!!!

Anixx · Apr 18, 2026

Edwin said:
Kind of a sh*tty rendering of the OP's Task Manager, but..., over 6 million KB of memory being hogged..., sumthin mighty suspicious goin on there!!!

The picture can be seen better if you right-click it and select "open image in a new tab". This works in many places.

Edwin · Apr 19, 2026

Anixx said:
The picture can be seen better if you right-click it and select "open image in a new tab". This works in many places.

It's not that! It's the fact that many of the most useful columns are missing or truncated..., plus the language barrier!

Kees · Apr 19, 2026

Edwin said:
It's not that! It's the fact that many of the most useful columns are missing or truncated..., plus the language barrier!

Plus the fact that the picture shows a very ancient version of Windows. Unless that setup was deliberately chosen via some tweaking app, it might point at use of Windows XP (or something around that version, even could be Windows95)! In the case of a tweaking app, that might be a reason for problems...

It's just that Firefox does not function on older systems anymore, so XP in fact is not possible...

Would be a great help if @Anixx would fill in the computer specs in his profile!

KevTech · Apr 19, 2026

Kees said:
Unless that setup was deliberately chosen via some tweaking app, it might point at use of Windows XP

I see desktop windows manager in the list which I don't think was in XP.
Also see Edge which if not using is just running in the background.

Edwin · Apr 19, 2026

Kees said:
Unless that setup was deliberately chosen via some tweaking app, it might point at use of Windows XP

Yeah..., I think it's a theme.
Either way, there's some terrible memory leaks happening, whether it's the Firefox version, multiple outdated extensions, corrupt config files or a combination thereof!

The OP should just install a fresh stable copy.

Firefox takes all memory, crashes the system

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