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memory leak

  • 17 uphendule
  • 66 zinale nkinga
  • Igcine ukuphendulwa ngu ninjawriter222

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Like so many others, I find the ongoing and worsening memory leaks a real disappointment -and now getting worse since V28 on both of my W7 machines.

I am now on FFox V30, and while it starts out at about 300MB, after a few hours it grows to be typically 2.xGB.

I have run the about:memory several times, but don't know how to use the results to any advantage. It appears that about 7 tabs each use about a 1/3-GB of memory.

I typically will have 5-6 windows open, a total of 20-30 tabs.

I have seen several threads on this, but none with any resolution, and dating back to V4 (about 2006)!

Is there any hope, or way to resolve, or just need to jump to Chrome?

All Replies (17)

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Several windows open, each w/ sites opened, will use a good bit more RAM. I tested just opening 2 more blank windows - it raised Private working set mem by 500 MB instantly, no tabs. Even mine w/ one window & avg of maybe 10 tabs, it creeps up to 650 - 800 MB.

That's w/ 8 GB RAM & I don't use disk cache in Fx - just memory. But, if I restart it, ram is always less.

With that many windows / tabs, you may have to restart Fx once in a while. You can use TabMixPlus to better manage saving sessions, so restoring last session will be easier.

There's also an about:config setting that releases some RAM, when Fx is minimized: config.trim_on_minimize;true if set = true, it gives back some when minimized. If entry doesn't exist, have to create it.

You can try it in safe mode, to rule out addon / plugins. sometimes they have memory leaks.

If fixes it, you'll create new profile (I suggest that vs. uninstalling / reinstalling all addons). And have to install addons back, couple at a time & see if any cause problem. Keep notes on what you do.

If safe mode doesn't fix it, you might try fully uninstalling Fx & reinstalling. Shut down everything you can, incl. AV / FW; get off the net.

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There are memory tweaks in every update, but websites keep getting richer, so it's hard to stay ahead.

I notice you have the FlashGot extension. I don't know whether you need that, but if it isn't critical, I suggest disabling it. Other users have linked it with substantial memory use. For the other four video downloaders, hopefully they are passive until invoked and are not all downloading in parallel.

On the about:memory page , do you ever find it useful to use the garbage collection buttons on the right side? I haven't figured out when they help.

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Are you saying it grow from 300MB to 2+GB over a couple of hours with the same tabs open ?

Is it any particular site or activity that you notice this on.

About memory gives the option to save and compare the reports. If you let Firefox startup and open all the tabs. Now save an initial about:memory result. Continue to use Firefox for a couple of hours and save it again. You could compare the two reports to see what has increased.

There is a button [Load and diff ... ]. Note about memory reports can be expanded or contracted and give information as tool tips on mousover.

What you probably need to do is try Firefox in

  • Firefox's safemode
  • With all plugins disabled

Browse for a couple of hours as a test and so convince yourself that in that configuration memory use is normal, and not shooting to over 2GB with 20 tabs open.

How does chrome compare in a very similar situation ?

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Chrome has no problems.

I used to have 10-12 pages open and ~100+ tabs, but now even 1/4 of that crashes after some time, usually ~1 day.

I disables almost all add-ins, but no change. I have several of the many forum posts on this,and the idea of running in safe mode, and trying to debug add-ins one-by-one is pretty troublesome.

Like many other reports, V28 seemed to be a main problem-causing release in this area, V29 & 30 continuing the trend.

Can't one tell from the memory report what memory usages are reasonable (or not)?

Yes, I already did a memory comparison between a new instance and an about to die one, I have posted it at: (too big to post on this page).

It is pretty clear that many-many have similar problems, and no solutions yet posted. I thought that posting a memory dump might help shed more light on it - but so far not.

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That confirms your description of

It appears that about 7 tabs each use about a 1/3-GB of memory.

I can see that will quickly lead to problems if you open quite a few tabs. Unfortunately this site and even do not take gzip files.

Posting the gzipped files that about:memory exports rather than a screenshot may make it easier for others to experiment with the sites you try to see if we than get high memory usage.

You say

I disables almost all add-ins, but no change. I have several of the many forum posts on this,and the idea of running in safe mode, and trying to debug add-ins one-by-one is pretty troublesome.

The problem is we do not know, and maybe you do not know yet.

  • Does Firefox behave in safe mode and with all plugins disabled or not ?
  • If Firefox does behave in safemode and with all plugins disabled
    Then you do need to narrow down the cause, and may do that by bisecting rather than serial single tests.
  • If not you have identified a problem.
    A Firefox problem possibly a regression.
    Or it could be a site problem but that is itself a Firefox issue if multiple sites cause the problem.

It is rather difficult at the moment to say how unusual your memory usage is. You mention it seems to have changed and got worse and also say Chrome has no problems however it could for instance have been some addon that has changed.

Memory issues are not easy to troubleshoot but if you wish to give it a try I will escalate this thread to ensure professional HelpDesk staff have oversight. Bugs may be filed for Firefox problems but we really do need to get more information before there is any realistic chance of getting a developer to be able to even see the problem. Glad to notice you are apparently not one of the 19 Million with potential memory issues related to ABP use .

Test With Portable ESR I can suggest one quick an dirty method of trying to see whether it is a Firefox issue since Firefox 25. Try it out in the unofficial Firefox portable ESR. You may quickly and easily install that as a separate additional browser it should be an interesting comparison, and does not affect the Mozilla Firefox browser or Firefox Release settings and addons.

Crashes If you crash lets seethe CrashIDs, (navigate to about:crashes ) but again these are better if you crash in safemode and with no plugins enabled. Of course you probably do not crash in that configuration.

Turn on Telemetry A final comment. Please ensure that you have the reporting turned on. The telemetry reporting was brought out after a Firefox 4 memory related regression was missed. It should at least give developers a chance of spotting any other Firefox regressions.

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Thank you for the note and information.

Re: "It appears that about 7 tabs each use about a 1/3-GB of memory.", that meant that of ~30-40 tabs, only those 7 show large memory usage.

I certainly understand the issues and challenges of debugging something like this, and was hoping that the memory reports could give some more concrete data for analysis.

I do have error reporting turned on, and thus have sent in lots of error reports, although sometimes I have to manually kill it as it just gets too slow - I don't know how to do that and also generate an error report(?).

I will try to find some time to test with the ESR as you suggest, and/to to do some debugging with /safe mode.

Here are some memory's,

I did not know about crash analysis - will look at it. A latest report: Crash Report:

Firefox 30.0 Crash Report [@ mozalloc_abort(char const* const) | mozalloc_handle_oom(unsigned int) | moz_xmalloc | GCGraphBuilder::NoteChild(void*, nsCycleCollectionParticipant*, nsCString) ]

(What is ABP?)

PS: While these reports are from my (main) desktop, where I used to have ~10 windows and ~100 tabs open, now the same thing happens on my W7 laptop, where due to lighter usage I only have 5-6 windows and 20-30 tabs open. I since rolled-back my desktop to a similar smaller number of tab/windows, and both still have the same issue (since V28). I.e. two machines, both same problem.

Okulungisiwe ngu guthrie

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I do not want to monopolise this thread others may have good ideas that will get you a solution faster.

This is a side issue, it does not affect you.

ABP is AddBlockPlus it is a popular addon with around 19 Million users on Firefox. It is behaving pretty badly with memory use but something that was not really noticed much untill recently. Probably the delay in realising it caused the problem was because many people do not test with and without addons to compare what is happening. It is noticeable once you do that and use about:memory to compare use with and without the addon IF you are using certainty types of site.

One of the Firefox developers posted a blog about the ADB issue recently.

My thoughts on your situation are that we stand a chance of getting a developer involved if we can show it is any of the following

  • A Firefox regression.
    Something where an earlier Firefox works ok but the current release does not.
  • A common Browser parity issue
    Something that Chrome handles well but Firefox does not. Say an issue seen on certain sites where Firefox uses a lot of memory but Chrome does not.

Alternatively We may just find a workaround for your issue by showing it is a particular addon causing the issue when using some sites. In which case there may be an alternative addon, or the addon developer may be able to find a solution.

I have tagged this thread as escalate so that it is drawn to the attention of HelpDesk staff.

Probably the best first step you could take would be to compare memory use whilst in Firefox's safe mode with all plugins disabled. That gives a base point for comparison, and takes out any problems caused by addons and tends to indicate the problem is Firefox related.

P.S. presume guigs2 comment downthread is related to Bug 969898 - gfx/heap-textures memory reporter can produce a negative number (I do not see the full ~4k list)

Okulungisiwe ngu John99

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Try to start your Computer in safe mode with network. Does Firefox still have problems?

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I also compared the two json files in the Load and diff option of about:memory first two: "

  -26.91 MB ── gfx-d2d-vram-draw-target
   -7.84 MB ── gfx-d2d-vram-source-surface
   -0.04 MB ── gfx-surface-win32
  -24.10 MB ── heap-allocated"

" and last two " -5.81 MB ── gfx-d2d-vram-draw-target

  1.45 MB ── gfx-d2d-vram-source-surface
  0.55 MB ── gfx-surface-win32
-26.02 MB ── heap-allocated
-12.23 MB ── heap-committed
    3.69% ── heap-overhead-ratio
 -0.64 MB ── js-main-runtime-temporary-peak

-132.70 MB ── private -158.44 MB ── resident"

These negative numbers are confusing, however this was one of the bugs that is fixed in version 30 where negative numbers came up inaccurately. A full list of the bugs that were fixed can bee seen here However overall the memory usage looks like it is decreasing, are you minimizing memory between these reports?

Again, we will not know wether or not this is an add on unless it also happens in Firefox Safe Mode.

Okulungisiwe ngu guigs

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Thank you.

I did a "reset to initial mode" on both machines, and it seems to make a big difference, although still usage is a bit high (600M). I'll see how stable this is, and then incrementally re-install plugins.

Not sure what the reset did - but I like it!

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Hi guthrie, This is awesome to read! Resting Firefox sets all the configurations back to the default state of a fresh install. (It removes some profile data and puts it into a file "Old Firefox Data" for more info on thisRefresh Firefox - reset add-ons and settings )

Thank you for your time as well!

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Thanks to all for the information and advice - it is a bit embarrassing that I had not already discovered and tried this.  :-) I will continue to try to reinstall plugins and see what happens. I don't suspect them of the main leaks, since I have had most of them for a long... time. Software is a complex and tricky business! It is not clear to me how setting these options to their values I had would have caused such a leak - but it does seem like something is a lot better now.

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The major changes after the reset are

  • Extensions (But not plugins) are uninstalled
  • Preferences are reset to defaults.

Note some none defaults will be shown as user set, even after the Reset; but will be derived values that have been user set programatically. You may find about:support useful. If you are interested in the prefs before and after, compare the contents of the file prefs.js in the current profile with the old one now on the desktop. (And any user.js)

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Another memory leak report, Firefox 31, Windows 7. Observed: with Firefox set as the standard browser, using MS Outlook to read/write email, Firefox kept using more and more memory, never releasing it, and rising from typically 200MB to 1.5GB in a few hours of email-reading mixed with casual browsing.

Reconfigured so that IE, rather than Firefox, is the system "standard browser" - therefore, email URLs etc. open in IE ... and Firefox memory usage is much more sane.

So, the evidence suggests that opening additional Firefox windows (by clicking on URLs in Outlook email) "grabs memory" - but does not release it when that Firefox window is closed.

The problem is bad enough that I *cannot* use Firefox as the standard browser - it consumes too much memory, too fast, and doesn't return it to the OS for use by other apps.

Behavior seems fairly readily reproduceable.

Noticed probably-similar behavior in Firefox 28/29/30, but did not try changing the system-default browser to IE in those tests.

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BillM, Thanks for the post. sorry you are having problems with Firefox.

Probably a good idea to start your own thread if you want to investigate this further (Standard reply but custom link for any reader of this thread to use)

  • Scroll through and read this thread. If you do not find a solution:
    1. Please start your own thread use this speciallink.
      It is direct and cuts out a few steps so it is quicker also contributors helping on the forum will recognise it as relating to this thread.
    2. Try to follow the prompts to include troubleshooting information.
      Try the green button [Automate this].
      If that fails mention it in the new thread.
    3. Post back in this thread but only to confirm a new thread was started.
      Someone will cross link the threads so anyone who wishes may follow both threads.

I empathise with users seeing memory leaks mainly because I myself seem to see similar sometimes in recent Firefox versions but have failed so far to pin it down reproducibly.

Possibly the missing link is that it is a leak with Outlook webmail. I do have Outlook webmail but do not normally leave it open. If I get some free time next week I may try to reproduce myself.

The difficulties I see are

  • Some few hours general browsing and email use could genuinely raise memory use to those sorts of levels. Especially with the known ABP issue.
    • Testing this hypothesis probably makes more sense using just webmail browsing.
    • If webmail and other browsing is the only way to reproduce then maybe try Webmail plus only one single other site.
  • You do not say if you are using about:memory or some other tool to measure memory.
  • I do when watching in a general system monitor see Firefox releasing large chunks of memory it does not always rise and stay high.
  • You probably are not trying in Firefox's safemode and with all plugins disabled.

I do not doubt what you say or that you have issues, just that it is not yet the sort of report that allows us to file a good bug with good Steps To Reproduce that we may pass on to an engineer to investigate.

Anyone else seeing this and able to reproduce the problem ?

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I seem to have found a resolution to this problem, at least for my Toshiba laptop. Luckily, mine never crashed but the memory usage was over 2.2 gig and scrolling was almost to a standstill. I've read so much on this problem, I can't remember what jogged my memory but something I read did. I went into the Add-ons manager and disabled the Block Site 1.1.8 add-on that I had running. I re-booted and have not had the problem since. That is the only change I made to my laptop, so that would indicate to me that the Block Site add-on was the culprit. I currently have 15 windows open and am not having a problem. Firefox is not good about releasing memory once it's allocated (they need to fix that) but at least now it's only about 650 mg. I hope this helps someone because I know I sure beat my head against the wall for weeks over it. Good luck.

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If the above doesn't work, please consider that Firefox has recently been having problems with adobe flash as well. Even if you aren't watching a video currently, if you had at one point since your most resent start up of fire fox it holds onto portions of that video's or web application's memory until it shuts down. The more videos or web programs that open that use flash (adobe flash) the more memory will be used until eventually you're stacking over 5,000 mb's in your RAM. This is not the fault of any add-on's such as Java or Add Block Plus.


1) Restart Firefox

2) Youtube seems to be the biggest culprit/cause of the memory leakage (or extra storage of memory through flash player onto your RAM.) So simply switch to HTML5 format. Various ways of doing this but here are a few options.

2.1) Go to or google search it and at the bottom there should be a button that says something like, "play all videos in HTML5", your current settings should be/generally are set to use "default".

2.2) Use add-ons such as YouTube ALL HTML5. They are free to download and easy to find using google, other default search providers, or simply click on tools > add-ons to open Firefox's add-on center where you will be able to search and download for free.

2) Uninstall Flash player and/or it's add-on's/extensions so they won't function with firefox (not as recommended as many web applications use Flash. Unless you know exactly what to reroute all web applications through, just don't do it. Leave it on so you may default back to it if necessary. If you do disable it however then most websites, such as youtube, should default to another player or HTML5 format.)

3) install an add on that stops flash player. (YouTube center used to work great, but now you tube has learned how to block most of it's applications)

3.1) Install video without flash (My favorite. However, youtube comments and other services won't work unless you disable it which can be done by pressing the add on's button that can be installed next to your search bar. You may need to reload the webpage once enabled/disabled. As this is such a hassle, even though I really like this player as it's lightning fast on my computer and super High Def, the hassle of having to disable and re enable is too much a hassle for the average user.)

3.2) Another option is to install VLC youtube shortcut (VLC player, which is free to download, will be needed for this one) or other similar programs. What it does is will allow your web videos to stream directly through a program on your coumputer (such as VLC my favoite rendering program)

Please take note that I have tried dozens of solutions and I have found no others that work and that Flash is indeed the main problem. Other solutions will improve performance marginally, by about 20%, but why settle for less then 100% of your computers capacity?