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I am receiving a "couldn't load XPCOM" error. I know that I can reinstall Firefox but how do I save my bookmarks?

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  • Last reply by cor-el

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I am receiving a "couldn't load XPCOM" error. I know that I can reinstall Firefox but when I went to do that it erased all of my bookmarks so I did a system restore. How do I save my bookmarks?

I am receiving a "couldn't load XPCOM" error. I know that I can reinstall Firefox but when I went to do that it erased all of my bookmarks so I did a system restore. How do I save my bookmarks?

Chosen solution

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.


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You can backup your data by following these directions: Back up and restore information in Firefox profiles

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Chosen Solution

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.


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I reinstalled, it still wont open.

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Hi rrfny

You need to make sure to delete the Firefox program folder to remove all the files that are possibly leftover after uninstalling.

Also make sure that your security software isn't causing problems with installing Firefox.

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