Firefox crashes

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This article is about Firefox closing itself unexpectedly. If Firefox remains open but becomes unresponsive, see Firefox hangs.

When Firefox crashes, it may bring up some windows that include one of the following sets of text:

Windows:
  • Firefox has encountered a problem and needs to close
Firefox 2:
  • Quality Feedback Agent
Firefox 3:
  • Mozilla Crash Reporter

These windows do not cause the crash; they come up after a crash, however they all indicate a crash. Sometimes, you may get none of these and Firefox can close unexpectedly.
Since crashes can be caused by numerous issues and can appear quite random, this article will focus on a few ways you can try to narrow down the problem as well as steps you can take to correct it. It ends with ways to get information about your crash to help Mozilla support staff when you get help.

Table Of Contents

Possible causes of crashes

Not using the latest version of Firefox

Firefox updates are regularly released and a number of the fixes are crash related. One of the first, and easiest, things to check is to make sure you're using the latest release. See Upgrading Firefox for details.

Problematic or out of date extensions or themes

Extensions and themes can often cause crashes and other errors. This is especially true if you recently installed or updated an extension. Follow the steps in the Troubleshooting extensions and themes article to determine whether an extension or theme is causing your problem. The following is a list of extensions known to cause Firefox crashes in some instances; it should not be considered comprehensive:

  • XPL LinkScanner
  • RealPlayer Browser Record Plugin (installed with RealPlayer)
Firefox 3:
  • PicLens
  • Free Download Manager

Problematic or out of date plugins

Plugins are programs that let Firefox display video and sound and do other things. If you find that certain, specific pages cause Firefox to crash every time you visit them, they may need a common plugin. Follow the steps at the Troubleshooting plugins article to determine whether a plugin is causing your problem.

The following plugins may cause crashes in some instances:

  • ActiveX: Firefox does not provide ActiveX support and if you have an old ActiveX plugin installed, you may experience problems such as crashes as well as be subject to a significant security risk. See ActiveX for more information and for instructions on how to remove the ActiveX plugin.
Windows:
  • VLC Media Player: On Windows, the VLC Media Player Plugin may conflict with the Windows Media Player plugin when playing WMP files. You will need to disable or remove the VLC Media Player Plugin to prevent this.


See the Troubleshooting plugins article for instructions on how to disable or remove plugins.

Windows:

Malware: viruses or spyware

A number of different viruses and spyware are known to crash Firefox. Ensure that your system is kept clean of spyware and viruses using spyware removal software and anti-virus spyware.

nsBrowserOpt.dll

nsBrowserOpt.dll is malware that installs itself in the Firefox components directory and can cause Firefox to crash. If your antivirus or spyware removal software is unable to remove it, follow the below steps to remove it manually:

  1. Close Firefox by opening the File menu and choosing Exit.
  2. Open My Computer or Windows Explorer.
  3. Browse to the directory: C:\Program Files\Mozilla Firefox\components
  4. Delete the file nsBrowserOpt.dll.

Firefox 3, Windows:

Your system clock is not correct

If your system clock is off by more than 2 days when you visit a secure web site (i.e. https://...), this may cause Firefox to crash when you:

  • visit the secure web site
  • try to view a certificate
  • close Firefox

To fix this, make sure your system clock is set to the correct date and time.

  1. Right-click on clock on the Windows System Tray, and select Adjust Date/Time. The Date and Time Properties window will open.
  2. Set the date, time, and timezone.
  3. Click OK, to close the Date and Time Properties window.

Firefox 3, Mac OS:

Crash on startup when using Shapeshifter

Unsanity Shapeshifter is currently not compatible with Firefox 3; it will cause Firefox to crash on startup. You need to disable Shapeshifter until an update is available. You can contact Unsanity about this issue here.

Other causes

Firefox 3, Windows:

Crash during startup with Google Desktop installed

Firefox can crash on startup when some files from older versions of Google Desktop are still present. This can happen even if you have the most recent version of Google Desktop. To resolve this issue:

  1. Uninstall the old Google Desktop
  2. Download and Install the new version of Google Desktop

Crash when downloading

Firefox can sometimes crash when you try to download files because its download history has become corrupted. To fix this, you must manually delete the downloads.rdf file from your profile:

  1. From the menu at the top of the Firefox windowbar, select FileFirefox and then select the ExitQuit FirefoxQuit menu item.
  2. Open the Firefox profiles folder. For more information, see profile folder.
  3. If the Profiles folder contains multiple folders, open the folder for the active profile.
  4. In the profile folder, find the downloads.rdf file and delete it.
Windows:

Crash when using Yahoo!® Mail

If Firefox crashes when using Yahoo!® Mail, see main article.

Windows compatibility mode (Windows XP)

On some systems, Firefox crashes if it's not run in Windows 2000 compatibility mode.

  1. Close Firefox by opening the File menu and choosing Exit.
  2. Right click the icon you use to start Firefox and choose Properties.
  3. Click on the Compatibility tab.
  4. Select Run this program in compatibility mode for.
  5. Choose Windows 2000 in the drop down.
  6. Click OK. Now that Firefox is set to run in Windows 2000 compatibility mode, it may no longer crash.

Crashes on Tablet PCs

On some Tablet PCs, Firefox will crash suddenly. This is a known bug and is fixed in Firefox 3.0.1. To get the latest version, see Upgrading Firefox.

Getting information about your crash

A number of different alert windows my pop up when Firefox crashes that can help provide information about your crash. This information can be helpful when you get help.

Firefox 2:

Quality Feedback Agent

The Quality Feedback Agent is used to provide Mozilla with key information. If you have the Talkback extension enabled, you'll have the option to submit an incident report after a Firefox crash. When you get help, the incident ID will be very helpful in narrowing down the cause of the crash and fixing it.

Firefox 3:

Mozilla Crash Reporter

The Mozilla Crash Reporter module activates on a Firefox crash. To submit information to Mozilla about the crash, check the box next to Tell Mozilla about this crash so they can fix it, then either click Restart Firefox or Quit Firefox as desired.


To access the Report ID, do the following steps:

  1. In your Firefox address bar, type about:crashes. You should see a window like the one below listing the crash reports that you've submitted.
  2. The report ID is the number listed, with the date and time to help you identify the correct report. It is also a link to the crash report. When you get help, having the report ID or the crash report URL will make it much easier to narrow down the cause of the crash and fix it. If you experience a crash multiple times, providing multiple crash reports will help us pinpoint the cause as well.
Windows:

Windows crash alert

Windows will put up an alert with the text similar to Firefox has encountered a problem and has to close. As you're not submitting any information to Mozilla, support helpers will not be able to access the crash report when you get help. However, there is still a lot of useful information even on that popup that can be used.
When the Windows crash alert pops up, click on the click here link after For more information about this error,.


When the error details appear, copy down all the information from Error signature as shown below. Having this information ready when you get help will make it easier to narrow down the cause of the crash and fix it.




Based on information from Firefox crashes (mozillaZine KB)


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Page last modified on Thursday 17 of July, 2008 13:10:44 PST.
Contributors to this page: Chris_Ilias , Callek , df1099 , Cww , Bo , AliceWyman , np and tosher .
- This is a support/troubleshooting article -