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assertion failed error


I keep getting this error in fire fox 14 and hoped it would go away in 15 but is continuing. i have tried to repair the install and uninstalling and re-installing with no joy. the error message reads.

Microsoft Visual C++ Runtime library Assertion Failed!

Program:... File: common\npn_gate.cpp Line: 267

Expression: pPluginShim

end message

Additional System Details


  • User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.83 Safari/537.1

More Information

  • Top 10 Contributor
  • Moderator
10745 solutions 96690 answers

You can do a check for problems with plugins.

Helpful Reply

i have tried all the steps in troubleshoot list and tried all the other trouble shooting links listed with no joy.

  • Top 10 Contributor
  • Moderator
10745 solutions 96690 answers

You did try to disable all plugins (Tools > Add-ons > Plugins)?

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

See "Creating a profile":

There may be extensions and plugins installed by default in a new profile, so check that in "Tools > Add-ons > Extensions & Plugins" in case there are still problems.

If the new profile works then you can transfer some files from the old profile to that new profile, but be careful not to copy corrupted files.


You can also try to reset Firefox:

Question owner

Problem still persists in new profile and yes i tried restarting with add on s disabled

  • Top 10 Contributor
  • Moderator
10745 solutions 96690 answers

Try to do a clean reinstall and delete the Firefox program folder (C:\Program Files\Mozilla Firefox\) before reinstalling a fresh copy of Firefox.

Download a fresh Firefox copy and save the file to the desktop.

Uninstall your current Firefox version, if possible, to cleanup the Windows registry and settings in security software.

  • Do NOT remove personal data when you uninstall your current Firefox version, because all profile folders will be removed and you will also lose your personal data like bookmarks and passwords from profiles of other Firefox versions.

Remove the Firefox program folder before installing that newly downloaded copy of the Firefox installer.

Your bookmarks and other profile data are stored in the Firefox Profile Folder and won't be affected by an uninstall and (re)install, but make sure that "remove personal data" is NOT selected when you uninstall Firefox.

Try to boot the computer in Windows Safe mode with network support (press F8 on the boot screen) as a test to see if that works.

Question owner

Tried the above without success

Question owner

Problem still persists if anyone out there has an answer and would like to thank col-el for your efforts