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Firefox Error: Can't load XPCOM

Firefox Troubleshooting
cor-el replied
Rampancy
Rampancy

My girlfriend's PC recently started getting this error when trying to boot Firefox. She's running Windows Vista and a fairly recent version of Firefox (27.x.x?). So far, I've done some searching and really haven't found a solution that's worked for her yet.

When you attempt to uninstall through the built-in uninstaller and through the control panel, nothing happens. Same with when you try to install a fresh copy over the old version. We were able to get the old version uninstalled with Revo Uninstaller and clear out it's registry items, but it didn't help. When trying to install the fresh copy, we still received another error saying that the installation failed because it was interrupted. Then, the same error when trying to boot Firefox. Couldn't load XPCOM.

Not really sure which way to go at this point. It seems like the only solutions I see posted just tell you to reinstall and restart the PC, which obviously haven't worked for us. Any other ideas to try would be greatly appreciated.

By the way, I'm currently away from home for a few days, so it may be awhile before I can test out any fixes on her PC.

My girlfriend's PC recently started getting this error when trying to boot Firefox. She's running Windows Vista and a fairly recent version of Firefox (27.x.x?). So far, I've done some searching and really haven't found a solution that's worked for her yet. When you attempt to uninstall through the built-in uninstaller and through the control panel, nothing happens. Same with when you try to install a fresh copy over the old version. We were able to get the old version uninstalled with Revo Uninstaller and clear out it's registry items, but it didn't help. When trying to install the fresh copy, we still received another error saying that the installation failed because it was interrupted. Then, the same error when trying to boot Firefox. Couldn't load XPCOM. Not really sure which way to go at this point. It seems like the only solutions I see posted just tell you to reinstall and restart the PC, which obviously haven't worked for us. Any other ideas to try would be greatly appreciated. By the way, I'm currently away from home for a few days, so it may be awhile before I can test out any fixes on her PC.

Modified by Rampancy

All Replies (1)

cor-el
cor-el
  • Moderator

Do a clean reinstall and delete the Firefox program folder before (re)installing a fresh copy of the current Firefox release.

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

If possible uninstall your current Firefox version 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 lose 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.

  • (32 bit Windows) "C:\Program Files\Mozilla Firefox\"
  • (64 bit Windows) "C:\Program Files (x86)\Mozilla Firefox\"

Your bookmarks and other personal 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.

If you keep having problems then also create a new profile.