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Firefox wont start "XPCOM" message pops up, need my user and passwords!!??

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My window 7 wasn't starting up properly so I did a system restore and now firefox wont start a message pops up stating "XPCOM" and I googled it and everything is telling to reinstall Firefox. I don't wont to reinstall it just yet because I need my passwords and username back. I cant find a solution on the forums either, or if there is I haven't found it or I simply didn't understood the solution itself. Please get back to me asap

thank you!

My window 7 wasn't starting up properly so I did a system restore and now firefox wont start a message pops up stating "XPCOM" and I googled it and everything is telling to reinstall Firefox. I don't wont to reinstall it just yet because I need my passwords and username back. I cant find a solution on the forums either, or if there is I haven't found it or I simply didn't understood the solution itself. Please get back to me asap thank you!

Chosen solution

Is a System Restore a rollback of recent updates or something more drastic?

You can do the following type of reinstall without touching your settings files. Important: do NOT uninstall Firefox first. That is not needed.

Clean Reinstall

(1) Download a fresh installer for Firefox 36 from https://www.mozilla.org/firefox/all/ to a convenient location. (Scroll down to your preferred language.)

(2) Exit out of Firefox.

(3) Rename the program folder

(64-bit Windows folder names)

C:\Program Files (x86)\Mozilla Firefox

to

C:\Program Files (x86)\OldFirefox

(32-bit Windows folder names)

C:\Program Files\Mozilla Firefox

to

C:\Program Files\OldFirefox

(4) Run the installer you downloaded in #1. It should automatically connect to your existing settings.

When starting Firefox, you may need to use the profile manager to switch back to your regular profile. Ignore: copy/paste glitch.

Any improvement?

Note: Some plugins may exist only in that OldFirefox folder. If something essential is missing, look in these folders:

  • \OldFirefox\Plugins
  • \OldFirefox\browser\plugins
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All Replies (2)

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This usually happens because of a failed Firefox update that left you with a mixture of old and updated files in the Firefox program folder.

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

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 this will remove all profile folders and you lose personal data like bookmarks and passwords including data in profiles created by 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 NOT to remove personal data when you uninstall Firefox as that will remove all Firefox profile folders and you lose your personal data.

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


more options

Chosen Solution

Is a System Restore a rollback of recent updates or something more drastic?

You can do the following type of reinstall without touching your settings files. Important: do NOT uninstall Firefox first. That is not needed.

Clean Reinstall

(1) Download a fresh installer for Firefox 36 from https://www.mozilla.org/firefox/all/ to a convenient location. (Scroll down to your preferred language.)

(2) Exit out of Firefox.

(3) Rename the program folder

(64-bit Windows folder names)

C:\Program Files (x86)\Mozilla Firefox

to

C:\Program Files (x86)\OldFirefox

(32-bit Windows folder names)

C:\Program Files\Mozilla Firefox

to

C:\Program Files\OldFirefox

(4) Run the installer you downloaded in #1. It should automatically connect to your existing settings.

When starting Firefox, you may need to use the profile manager to switch back to your regular profile. Ignore: copy/paste glitch.

Any improvement?

Note: Some plugins may exist only in that OldFirefox folder. If something essential is missing, look in these folders:

  • \OldFirefox\Plugins
  • \OldFirefox\browser\plugins

Modified by jscher2000 - Support Volunteer