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Firefox 25 still has memory leaks

  • 25 replies
  • 123 have this problem
  • Last reply by jpdemers

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It seems that Firefox still hasn't fixed it's memory leaks. I'm on Firefox 25.1 on Mountain Lion with 16 gigs RAM on a macbook pro with Retina. I've disabled all plugins and all add-ons and memory still seems to creep up as long as firefox is open. I also notice that CPU is always pretty high. In comparison to chrome and safari it's pretty ridiculous how much CPU and real and virtual memory Firefox needs. I do like the browser though.

Is anyone else having this problem still?

Please Note

For those sticking with Firefox

  • see this helpful advice post 505646 down thread by Wesley Branton
  • or for investigating a solution or needing your own fix see my post 521852 down thread

Thanks John, (A forum moderator.)

It seems that Firefox still hasn't fixed it's memory leaks. I'm on Firefox 25.1 on Mountain Lion with 16 gigs RAM on a macbook pro with Retina. I've disabled all plugins and all add-ons and memory still seems to creep up as long as firefox is open. I also notice that CPU is always pretty high. In comparison to chrome and safari it's pretty ridiculous how much CPU and real and virtual memory Firefox needs. I do like the browser though. Is anyone else having this problem still? ----- ===Please Note=== For those sticking with Firefox *see this helpful advice [/questions/978195#answer-505646 post 505646] down thread by ''Wesley Branton'' *or for investigating a solution or needing your own fix see my [ post 521852] down thread Thanks John, (A forum moderator.)

Modified by John99

All Replies (20)

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How much CPU is Firefox using?

Please feel free to file a bug report here.

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Anywhere between 7% and 10% while stagnant. More than that when it's actually browsing.

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In order to be able to find the correct solution to your problem, we require some more non-personal information from you. Please do the following:

  • Click the Firefox button at the top left, then click the Help menu and select Troubleshooting Information from the submenu. If you don't have a Firefox button, click the Help menu at the top and select Troubleshooting Information from the menu.

Now, a new tab containing your troubleshooting information should open.

  • At the top of the page, you should see a button that says "Copy text to clipboard". Click it.
  • Now, go back to your forum post and click inside the reply box. Press Ctrl+V to paste all the information you copied into the forum post.

If you need further information about the Troubleshooting information page, please read the article Use the Troubleshooting Information page to help fix Firefox issues.

Thanks in advance for your help!

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If you are using any add-ons with the Firefox program, it is possible that these add-ons are running while Firefox is idle.
This would be the explanation for the memory usage.

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I don't like posting all the information it collects - nervous about security. I do have some add-ons but not many - I don't want to post which I have exactly - I only have 3 enabled and one of them is Ad Block Plus 2.4. I really don't think they're the problem.

I appreciate your help but I think this is more a FF development issue than anything else I have done with FF.

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Create a new profile as a test to check if your current profile is causing the problems.

See "Creating a profile":

If the new profile works then you can transfer some files from an existing profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over the problem.

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Sorry for the delay in my response.

The information in the troubleshooting charts is not sensitive.
No information can be tracked back to you.

This information is extremely helpful for the support volunteers, as it provides information about changed settings, active extensions, operating system, Firefox information and your computer's graphics card(s).

Having this information would really help the support volunteers to solve your issue faster and more efficiently.

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Try Firefox Safe Mode to see if the problem goes away. Safe Mode is a troubleshooting mode, which disables most add-ons.

(If you're not using it, switch to the Default theme.)

  • On Windows you can open Firefox 4.0+ in Safe Mode by holding the Shift key when you open the Firefox desktop or Start menu shortcut.
  • On Mac you can open Firefox 4.0+ in Safe Mode by holding the option key while starting Firefox.
  • On Linux you can open Firefox 4.0+ in Safe Mode by quitting Firefox and then going to your Terminal and running: firefox -safe-mode (you may need to specify the Firefox installation path e.g. /usr/lib/firefox)
  • Or open the Help menu and click on the Restart with Add-ons Disabled... menu item while Firefox is running.


Once you get the pop-up, just select "'Start in Safe Mode" Safe Mode Fx 15 - Win

If the issue is not present in Firefox Safe Mode, your problem is probably caused by an extension, and you need to figure out which one. Please follow the Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems article for that.

To exit the Firefox Safe Mode, just close Firefox and wait a few seconds before opening Firefox for normal use again.

When you figure out what's causing your issues, please let us know. It might help other users who have the same problem.

Please report back soon.

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I found FF 25 to be unusable due to the memory leak issue -- memory usage is the highest at start-up and increases at an alarming rate. It's the worst of any of the previous versions. I would gladly forgo any new features and glitz in the next version if this problem is finally fixed. I downgraded to FF 22.0 and it's behavior is stable and predictable. This is a show-stopper issue for me.

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I have been having the same issues with increased memory usage even when idle. See the report below and please advise me of any changes I should make.


Reset Firefox to its default state

If you're having major problems which you can't resolve, start fresh with only your essential information. Troubleshooting Information This page contains technical information that might be useful when you're trying to solve a problem. If you are looking for answers to common questions about Firefox, check out our support website. Application Basics Name Firefox Version 25.0.1 Update History User Agent Mozilla/5.0 (Windows NT 6.1; WOW64; rv:25.0) Gecko/20100101 Firefox/25.0 Profile Folder Enabled Plugins about:plugins Build Configuration about:buildconfig Crash Reports about:crashes Memory Use about:memory Extensions Name Version Enabled ID Adobe Acrobat - Create PDF 2.0 true web2pdfextension@web2pdf.adobedotcom Content Blocker false DigitalPersona Extension false Kaspersky URL Advisor false Virtual Keyboard false Important Modified Preferences Name Value browser.cache.disk.capacity 358400 browser.cache.disk.smart_size.first_run false browser.cache.disk.smart_size.use_old_max false browser.cache.disk.smart_size_cached_value 358400 browser.places.smartBookmarksVersion 4 browser.sessionstore.upgradeBackup.latestBuildID 20131112160018 browser.startup.homepage browser.startup.homepage_override.buildID 20131112160018 browser.startup.homepage_override.mstone 25.0.1 dom.mozApps.used true extensions.lastAppVersion 25.0.1 font.size.variable.x-western 20 gfx.direct3d.last_used_feature_level_idx 0 network.cookie.prefsMigrated true places.database.lastMaintenance 1386136161 places.history.expiration.transient_current_max_pages 100530 plugin.disable_full_page_plugin_for_types application/pdf plugin.importedState true plugin.state.npadobeaamdetect 0 plugin.state.npappdetector 0 plugin.state.npatgpc 0 plugin.state.npbattlelog 0 plugin.state.npbrowserplugin 0 plugin.state.npgeplugin 0 plugin.state.npgoogleupdate 0 plugin.state.npican 0 plugin.state.npitunes 0 plugin.state.nppdf 0 privacy.sanitize.migrateFx3Prefs true storage.vacuum.last.index 1 storage.vacuum.last.places.sqlite 1386087795 Graphics Adapter Description ATI Mobility Radeon HD 4200 Series Adapter Drivers aticfx64 aticfx64 aticfx32 aticfx32 atiumd64 atidxx64 atiumdag atidxx32 atiumdva atiumd6a atitmm64 Adapter RAM 320 Device ID 0x9712 Direct2D Enabled true DirectWrite Enabled true (6.2.9200.16571) Driver Date 4-29-2013 Driver Version 8.970.100.1100 GPU #2 Active false GPU Accelerated Windows 1/1 Direct3D 10 Vendor ID 0x1002 WebGL Renderer Google Inc. -- ANGLE (ATI Mobility Radeon HD 4200 Series Direct3D9Ex vs_3_0 ps_3_0) windowLayerManagerRemote false AzureCanvasBackend direct2d AzureContentBackend direct2d AzureFallbackCanvasBackend cairo AzureSkiaAccelerated 0 JavaScript Incremental GC true Accessibility Activated false Prevent Accessibility 0 Library Versions Expected minimum version Version in use NSPR 4.10.2 4.10.2 NSS 3.15.3 Basic ECC 3.15.3 Basic ECC NSSSMIME 3.15.3 Basic ECC 3.15.3 Basic ECC NSSSSL 3.15.3 Basic ECC 3.15.3 Basic ECC NSSUTIL 3.15.3 3.15.3

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If none of the above resolves your problem, please create a new thread with the details specific to your problem.
This will allow us to give you assistance more relevant to you.

Please post the link on this thread when you are done.
Thank you.

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I'm running 26.0 on Windows 7 and mine started doing this yesterday after an update. It chewed up 12GB of RAM and caused a hard crash. I have no restarted it in safe mode and it has stopped leaking, so it must be a bad add-on.

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If the above information does not resolve your issue, please consider creating a new thread containing the specific details of your issue.

Doing so will allow the Mozilla volunteers to give you solutions that are more helpful to you. This may help them to solve your problem faster and more efficiently.

Please, feel free to post the link to your thread on this thread for volunteers interested in assisting you.

Thank you.

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Actually it turned out the culprit was a file dllhost.exe Com surrogate, When searching that term I found a thread about it on MS and it turned out to be a Windows update that did it.

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I like Firefox and the whole idea of an open source community BUT 26 has some kind of serious problem. It is gulping memory. I spent a lot of time doing the troubleshooting described here and none of it helped. And different people say they found different fixes - some say add-on "Ghoster" was the problem - this guy says dllhost.exe was the problem. Sadly, I have dropped Firefox - am using Opera and it works great. The Mozilla folks have to figure out what the problem is.

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I have discovered that the culprit that aggravates the memory utilization issue with Firefox on my PC is the add-on known as 'we download manager pro'. It is an insidious add-on and should be removed AND uninstalled in Control Panel. It will rear its ugly head every once in a while so when unusual Firefox performance is observed (heavy memory use, lots of pop ups, etc.), check your add-ons to see if its there and remove it.

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Just some quick comments.

Please ensure telemetry is turned on that way real data about such real world use and problems is collected in an anonymised form. That system was IIRC introduced after a Fx4 memory regression issue.

It is no coincidence that the term YEINU was coined and recently blogged about by a developer working on Firefox memory problems.

I am sure problems are very real and badly affecting you. The problem is the easy issues affecting everyone are found and resolved, but the difficult to find and reproduce problems persist and will need your help in fixing.

We need to get a demonstration that is reproducible. That engineers can in turn reproduce and work on.

By all means read this thread and try the advice, and look at linked articles and threads but if you want an investigation and a solution please start your own thread as already requested. Unfortunately you will be expected to give a hand and try troubleshooting steps to demonstrate the problem. Doing so may solve the problem for you, or may enable us to get a bug filed that a developer can investigate and fix.
(But sorry we can not file a bug just saying Firefox has memory leaks. We need more information before we are in a position to do that. Otherwise we waste everyone's { yours, mine, bug triagers } time asking that an undefined unreproducible problem be somehow investigated. )

So instead of grousing that Firefox doesn't work and there is no easy fix lets try to help ourselves and find solutions or get it fixed.

If you wish to start a new thread and help

  1. Please use this special link
    Or if you have moved on to Firefox 27 Special Link fx27
    The link is quick as it is direct and cuts out some steps. It will be recognised a relating to this thread.
  2. and follow the prompts to add troubleshooting information to your post
    (There is a green button to automate that task)
  3. Post back here but just to confirm that you have done so.
    We can keep threads cross linked and post any solutions in this thread if discovered in a child thread.

More small print If you are not even willing to try the current version of Firefox at least for troubleshooting do not bother wasting time posting.
The engineers will not investigate issues on unsupported versions of Firefox unless the problem also affects supported Releases.

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We should be able to either

  • solve your problem
  • or prove that it is not a Firefox development issue.

We may well even be able to do that without you needing to disclose any information you consider sensitive.

Are you still interested in attempting to get to the bottom of this or would you rather we just drop the subject. Close this thread, and leave you struggling with an unexplained memory leak problem.


Cross link to potentially related threads

  • Firefox 26 on OS X 10.9.1 still has huge memory usuage (leak) which leads to crash

Modified by John99

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I found a solution that worked for me.

I've had big problems with memory leaks in Firefox. The RAM being used skyrocketed and made me have to shutdown(often CTRL+ALT+DELETE and end task) in order to restart firefox because it was using so many resources. I searched for a long time with no good answers. What I finally tried that worked for me is: I went to tools, options, then clicked on tabs. I checked the box that says" Don't load tabs until selected". Firefox still uses more RAM than it should (IMO), but it doesn't spiral out of control and is stable again. Hope this works for other people and helps. Firefox is the best browser, but I downloaded chrome out of desperation before I finally found this to work.

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Hi nate100,
Comments are welcome, and I am glad that helped you.

The "Don't load tabs until selected" should ordinarily be the default setting.
It should also help with start up speed.

I imagine it does help where

  • There are a lot of open tabs in use every session. Especially if many are not actually displayed and active but have heavy content.
  • Some of those tabs relate to a Webpage or an Addon that causes a memory leak.

The use of the setting is mentioned in this article

That is mostly going to help those with a lot of open tabs.
It is always a good idea to try to avoid opening masses of tabs, especially if Firefox is in any way struggling or using High amounts of Memory or CPU.
Over reliance on open tabs may also be an problem if a sessionrestore issues develops. It may not always be possible to restore tabs from a previous session.

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