This article covers the situation where Firefox displays a message about crashing when you try to start it.
- If Firefox does not start at all, see Firefox won't start - find solutions.
- If you are able to get Firefox to load but are seeing a crash-related message after you have tried to use it, see our page on general Firefox crashes.
When Firefox crashes, you may see a window containing one of the following sets of text:the following text:
- Firefox has encountered a problem and needs to close
- Mozilla Crash Reporter
Table of Contents
Not running the latest version of Firefox
A number of startup crashes no longer occur in the latest Firefox version. Please update Firefox to see if that addresses your crash.
Determining if Firefox can load in Safe Mode
When Firefox crashes at startup, the possible causes depend on whether Firefox is able to load in Diagnose Firefox issues using Troubleshoot Mode.
Click the menu button 
, click , select and click in the Restart Firefox in Troubleshoot Mode? dialog.
firefox -safe-modeYou may need to specify the Firefox installation path (e.g. /usr/lib/firefox).
Firefox opens in Safe Mode
If Firefox does not crash when you try to open it in Safe Mode, the most likely cause of the problem is an extension or a theme. Please see our page on Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems for help with this problem.
If you are unable to fix the problem after following the steps on that page, start Firefox in Safe Mode, by following the instructions below:
Click the menu button
, click , select and click in the Restart Firefox in Troubleshoot Mode? dialog.
Note: You can also start Firefox in Troubleshoot Mode by holding down the Shift key while starting Firefox.holding down the option key while starting Firefox.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).- When the Firefox Safe Mode window appears, press the button .
Once you're in Safe Mode, follow the instructions on collecting information about your crash and provide that information when you get help.
Firefox does not start in Safe Mode
If Firefox also crashes when you try to open it in Safe Mode, the following sections include information that can help you resolve the problem.
Using Hulu Desktop Plugin
The template "crashsig" does not exist or has no approved revision. @ @0x8fe053f6 Some versions of Hulu Desktop Plugin will cause Firefox to crash on startup. To correct this remove the huludesktop.webplugin file:
- Open Finder and go to /Library/Internet Plug-ins/.
- Remove the file: huludesktop.webplugin
- Download a new version of Hulu Desktop where this issue has been fixed.
Crash 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.
Running an older version of Google desktop search
The template "crashsig" does not exist or has no approved revision. GoogleDesktopMozilla.dll@0x5512, GoogleDesktopMozilla.dll@0x5500, GoogleDesktopMozilla.dll@0x56bc or GoogleDesktopNetwork3.dll@0x3dfb
Crash when using Spector Pro
Some versions of the Spector Pro for Windows computer monitoring program can cause Firefox to crash on startup. If you use this program, try updating to the latest version or contact SpectorSoft Support.
Backdoor.Ulrbot.C
Backdoor.Ulrbot.C is a malicious piece of software that can infect your computer and may not be detected by your antivirus program. In addition to installing a backdoor so that your computer is open to all sorts of dangerous manipulation, Backdoor.Ulrbot.C also crashes Firefox 3. The only fix is to manually delete the virus DLL file in Windows Safe Mode. Unfortunately this file has a randomly generated name and size so it may be hard to identify. The following steps detail how to find suspicious DLL files that may be causing this, verify them and remove them if necessary. These steps will only work if you get the Mozilla Crash Reporter dialog box and you have submitted a crash report to Mozilla.
- Get the crash report. (See Getting your crash report)
- Wait for the crash report to finish processing if necessary. If it's taking an unusually long amount of time, you may have typed in the wrong report ID.
- Once you have the report open, click on the Modules tab at the top of the page.
- This is a list of all the modules that are loaded with Firefox. Look for modules that have no version information (the second column is blank). If you do not see any such modules, you do not have Backdoor.Ulrbot.C, please try other solutions on this page.
- If you do see modules with no version information, copy their names into a search engine such as Google. If you get no or very few results, it's likely that the module is a randomly named one and likely to be malware.
- If you have a file that fits this criteria, search your computer for the file(s) and write down its location.
- In your working web browser, go to http://virusscan.jotti.org/ and upload the suspected file(s) at the top and click . While that online scanner is not perfect, it has been able to identify Backdoor.Ulrbot.C in a majority of cases. For all files that are identified as containing Backdoor.Ulrbot.C, proceed with the following steps. If none of the suspected files contain Backdoor.Ulrbot.C, you may still want to attempt the following steps in case you have a previously-unseen variant of this virus.
- Start your computer in Windows Safe Mode (not Firefox Safe Mode) by following the instructions on Microsoft website for Windows Vista or Windows XP.
- In safe mode, locate each of the file(s) that you identified earlier. If they were identified as containing Backdoor.Ulrbot.C, you can safely delete them. If not, rename them from xxxxx.dll to xxxxx.dll.old so you can rename them back if necessary.
- Restart your computer in normal mode.
- Start Firefox. If it starts, you have successfully identified and fixed the cause of the crash.
Other malware: viruses or spyware
In addition to the specific cases listed above a number of different viruses and spyware may crash Firefox. Ensure that your system is kept clean of spyware and viruses. For more information, see Troubleshoot Firefox issues caused by malware.
Other causes
If the specific cases listed above do not help, try general troubleshooting of Firefox crashes or get more information about your crash and provide that information when you get help. If you have changed your homepage to not be the default, you may also be experiencing a crash when loading your homepage. In that case, see Troubleshoot Firefox crashes (closing or quitting unexpectedly).
Getting your crash report
- On Windows 2000/XP, click the Windows button and select .
On Windows 7/Vista, press + R on the keyboard. In the Run box, type in "%APPDATA%\Mozilla\Firefox\Crash Reports\submitted" including the quotation marks and click .In the finder go to ~/Library/Application Support/Firefox/Crash Reports/submitted.Go to ~/.mozilla/firefox/Crash Reports/submitted.
- In the resulting folder will be a text file for each crash report you have submitted. Using the menu, arrange them by date to find out which is the newest file; and double-click on it to open it.
- Your crash ID is the part after the bp-. For example, if the file contents is:
Crash ID: bp-277ca492-ef87-40ea-b667-051b437f2b78Then your crash ID is 277ca492-ef87-40ea-b667-051b437f2b78. - In another browser, go to http://crash-stats.mozilla.com/report/index/<your crash ID here> (e.g. http://crash-stats.mozilla.com/report/index/277ca492-ef87-40ea-b667-051b437f2b78 )
- You will be taken to a page on crash-stats.mozilla.com, saying that "Your report is being processed". When it is finished processing, your crash report will be displayed.
