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Failed to read configuration file

Posted

I cannot open Firefox, I get the message that Firefox failed to read configuration file. I uninstalled and reinstalled latest version and still cannot open with the same error. What can I do to fix this without losing all my bookmarks? Hopefully they aren't already gone??

Additional System Details

This happened

Every time Firefox opened

This started when...

I used RegCure Pro to restore my system to a few days back

Application

  • User Agent: Mozilla/5.0 (Windows NT 5.1) AppleWebKit/534.57.2 (KHTML, like Gecko) Version/5.1.7 Safari/534.57.2

More Information

jscher2000
  • Top 10 Contributor
2365 solutions 20923 answers

I didn't think using the Windows System Restore feature could break Firefox, because Firefox generally doesn't rely very much on the Windows registry or system folders.


Someone might have a faster solution that what follows, so you might wait a few more hours to see whether one is posted.


Could you test whether you can create a new personal Firefox settings folder (AKA profile folder)? Start up in the Profile Manager using:

Start > Run > firefox.exe /ProfileManager

You should see a dialog that allows you to create a new profile, as described in this article: Use the Profile Manager to create and remove Firefox profiles. Any time you want to switch profiles, close Firefox and return to this dialog. (I recommend not deleting anything until you are 110% certain you won't need it.)

Will Firefox start up in the new profile without an error message, or do you get the same error?

If Firefox works in the new profile, you can copy key settings files over to it from your old profile. This article describes the contents of the various files: Recovering important data from an old profile. To find your old profile folder, try this method.

With Firefox running in the new profile,

Help > Troubleshooting Information > "Show Folder" button

Navigate up one level to the profiles folder, and look for the one that ends with "default" or which has a last modified date corresponding to the last time you used Firefox.

Question owner

I still get the same error message

cor-el
  • Top 10 Contributor
  • Moderator
10756 solutions 96800 answers

You get such an error if there is a mozilla.cfg file in the Firefox program folder to initialize prefs and there is a problem with that file.

If you didn't create the file yourself then best is to do a clean reinstall of Firefox and make sure to remove the Firefox program folder to remove all the files in it.

Do a clean reinstall and delete the Firefox program folder 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.


nukesig 0 solutions 2 answers

Over 25 times of uninstalling and re-installing--Goodbye Mozilla!

cor-el
  • Top 10 Contributor
  • Moderator
10756 solutions 96800 answers

Helpful Reply

Did you do a clean reinstall and made sure to delete the Firefox program folder?

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


nukesig 0 solutions 2 answers

Romoving the file out of the program files was the key--I assumed that the uninstall would have done that--Thank You

cor-el
  • Top 10 Contributor
  • Moderator
10756 solutions 96800 answers

An uninstall only removes file that the Firefox installer has installed and not files that were installed via other sources like in this case when a mozilla.cfg has been injected somehow.