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Firefox crashes, CPU utilization at max

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Update #2:  I keep hearing from more people that their Firefox installation is broken but for some reason there’s not much noise around the web about this. Disabling add-ons seems to be a partial solution only, I suggest you go back to or try the recently released Firefox 3.0 Beta 1. You will see this last one is very very speedy but lacks support for a majority of add-ons out there which hinders its immediate potential.

Update: On a second thought (and further testing) Firefox still seems to be using too much CPU power, but disabling the add-on permits the browser to remain functional and not crash like before.

Last week Firefox received two updates, version which fixed security vulnerabilities and later a version .11 which fixed a regression bug. During the weekend however I reported in our frontpage’s weekend picks post that even this latest version was broken:

Mozilla Firefox released (broken!): This one fixes some regressions from the other recent releases. If you are running anything earlier than I suggest you don’t upgrade to any of the newer versions until an even newer revision is released. Several complaints from users about random crashes and high CPU utilization have risen in the past week. This editor is just another of such users feeling the pain in multiple OS versions, for sure the latest updates are to blame.

As stated I started having trouble in all of my Firefox installations, that includes multiple platforms like XP, OS X and Vista. Being a Firefox junkie, I couldn’t get myself to use an alternative browser for too long, so I had to fix Firefox. As it happens the bug doesn’t seem to be present in Firefox itself but an incompatibility with the Tab Mix Plus extension, one of the most useful and popular Firefox extensions out there.

So if you are suffering from insanely high CPU utilization in Firefox as of recent, there you have the answer. Disable the add-on and wait until an updated version is out.

Could this be sloppy patching and coding as a side effect of Firefox 3 becoming a priority?

Written by Julio Franco

December 3rd, 2007 at 1:49 pm

Posted in blog

18 Comments so far

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  1. I’m getting the occasional lock-up (cpu spinning) and spurious crashes (seg fault) when I click on links or enter a URL in the address bar. Re-open the browser, try the link again, and it’s fine.

    Since I don’t get a traceback or core file on Ubuntu, I haven’t reported the bug. (Why bother if it’s pretty much a given that a developer or bug triager will mark such a bug report as WORKSFORME or NEEDINFO?) Running firefox from a terminal window doesn’t reveal the cause either.


    4 Dec 07 at 8:20 pm

  2. I haven’t noticed this in Linux but XP, Vista and OS X, which made my believe it wasn’t the specific platform to blame. Running add-on-less Firefox 3 beta now and it flies compared to 2.0

    Julio Franco

    4 Dec 07 at 9:35 pm

  3. Which add-ons did you have installed and which ones did you disable?


    6 Dec 07 at 1:00 pm

  4. I use a few add-ons, the basics include Tab mix plus, Roboform and download statusbar. Some other webmaster friendly tools like color eye picker, measure it, and Web Developer. It didn’t make a difference in Windows though with our without any of them the CPU utilization went through the roof even on clean install.

    I’m now using Firefox 3 beta in Windows which is not without its flaws yet as expected but I’m not unfamiliar with using beta software. In OS X I was forced to use Safari which seems very stable but just like IE is very hard to customize to one’s likings and comes “bundled” with a few typical Mac nuisances here and there.

    Julio Franco

    6 Dec 07 at 3:41 pm

  5. I have actually been experiencing the same problems myself. After some careful consideration and proper checks I noticed that what was killing Firefox wasn’t even an extension rather a library dependency that didn’t upgrade. My local search brought me to an upgrade log found in..

    (“X” being your local drive and “user” being your logged in user.)
    X:\Documents and Settings\user\Local Settings\Application Data\Mozilla\Firefox\Mozilla Firefox\updates\last-update.log

    Remembering that the failing dependency was (a fault caused by js3250.dll), I discovered in the log that the upgrade FAILED TO REMOVE THE PREVIOUS VERSION FOR THE UPGRADE! This, I’m almost positive, is the primary reason my client keeps dying when I go to site to site. Reading my event logs also proves this..

    Faulting application firefox.exe, version 1.8.20071.12718, faulting module js3250.dll, version, fault address 0x0003224c.

    I will be alerting Mozilla of my find shortly today, if they don’t take it into consideration I will be highly disappointed.

    Anthony White

    13 Dec 07 at 9:27 am

  6. Actually after reinstalling (after removing everything) for a third time, I still get a fault from js3250.dll Apparently it is the native JS module from Netscape (v4.0.0.0). Apparently their latest revision has made a crucial error causing faults on JS embedded websites (i.e. Gmail, Google Maps, etc.)

    Anthony White

    13 Dec 07 at 9:58 am

  7. Just in case anyone has been having this issue (it doesn’t appear to be affecting everyone), you can downgrade to a stable version of located below. Hope that will resolve this issue!!

    Anthony White

    13 Dec 07 at 10:41 am

  8. Hi Anthony,
    That’s basically what I recommended in my latest updates to this post (downgrade). Like you say the problem doesn’t seem to be as widespread that Mozilla has taken weeks now without saying a thing about it.

    Julio Franco

    13 Dec 07 at 5:00 pm

  9. Ah, sorry about that. I didn’t catch that update. Anyways, v2.0.0.12pre is in the nightly build section, I tested the client and again the problem is still arising. Hopefully I’m just getting ahead of myself, the js3250.dll is still at v4.0.0.0, maybe the fault lies within the lower layers of Firefox.

    Anthony White

    13 Dec 07 at 8:13 pm

  10. I am running and have just had it lock up with max cpu. I am not running any add-ons apart from the default talk-back thingy, tho I have noticed the cpu getting quite busy on Flash sites…

    Chris Wilson

    16 Dec 07 at 7:32 am

  11. There have been CPU problems with Firefox for some time, though it seems to have gotten worse with the last release. Finally, someone has filed a bug on this, here:

    (Please vote for this bug.)


    30 Dec 07 at 8:56 am

  12. Hi, I am running and am experiencing between 5-6 ‘unexpected shut downs’ of firefox per day! I have been in the office for an hour now and already I have had two. It driving me mad.


    24 Jan 08 at 5:55 pm

  13. Nina, I suggest you make a clean install of Firefox using a previous version, would be advisable. Either that or upgrade to one of the Firefox 3 Betas:

    Julio Franco

    24 Jan 08 at 6:46 pm

  14. In my case, is taking max CPU resource when FireFox is used. IE7 is okay.


    26 Feb 08 at 11:03 am

  15. I am using the FireFox on Windows XP.
    1) There is a major issue with the Browser consuming CPU – so much that the whole m/c just hangs. With no option but to ReBoot.
    2) While playing Streaming videos the memory usage of FF increases drastically.

    These days I have started using IE more and more. I hope we dont go back to those IE days.


    28 Jul 08 at 11:26 pm

  16. Anu, i think there are some problem in your system, i met the same problem 3 months ago. Everything was Ok after i reinstalled my system.

    Kathy Mead

    9 Sep 08 at 4:56 am

  17. My Firefox browser randomly freezes and shuts down 2-3 times per day. It especially happens when I have one or more tabs open. When I go into the task manager I have a application called Dumpprep.exe running. I think it is a virus. Does anyone know how to get rid of it.


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