Join the AMA (Ask Me Anything) with the Firefox leadership team to celebrate Firefox 20th anniversary and discuss Firefox’s future on Mozilla Connect. Mark your calendar on Thursday, November 14, 18:00 - 20:00 UTC!

This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Avatar for Username

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

This thread was archived. Please ask a new question if you need help.

Firefox won't load, error msg read can not load xpcom.

  • 1 reply
  • 5 have this problem
  • 8 views
  • Last reply by cor-el

Truckerfriend
Truckerfriend
more options

I had a problem with Firefox not opening so I did an Uninstall then when I tried to reinstall from the download site it will not install giving an error message reading that it could not load xpcom.

I had a problem with Firefox not opening so I did an Uninstall then when I tried to reinstall from the download site it will not install giving an error message reading that it could not load xpcom.

All Replies (1)

cor-el
cor-el
  • Moderator
  • Top 10 Contributor
more options

An error message about XPCOM missing or about platform version usually happens because of a failed Firefox update that left you with a mixture of old and updated files in the Firefox program folder. This can happen in case security software was keeping a handle of some of the files in the Firefox program folder preventing Firefox from replacing all the files. You can do a clean reinstall to ensure that all files are replaced. You may have to disable security software temporarily in case the problem persists.

Do a clean reinstall of the current Firefox release and delete the Firefox program folder before 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 the 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.

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

Your personal data like bookmarks is stored in the Firefox profile folder, so you won't lose personal data when you uninstall and reinstall or update Firefox, 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.