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Your Firefox profile cannot be loaded. It may be missing or inaccessible

  • 13 replies
  • 1 has this problem
  • 6 views
  • Last reply by cor-el

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Hello! I'm on Windows 10 Pro. When I try to launch Firefox I keep getting "Your Firefox profile cannot be loaded. It may be missing or inaccessible". I already tried uninstalling with Revo uninstaller and then reinstalling again.

Also tried manually deleting the profiles.ini file, trying and create a new one by putting in the run window: firefox.exe -P(it shows the error) and renaming the firefox folder to FirefoxOLD.

Hello! I'm on Windows 10 Pro. When I try to launch Firefox I keep getting "Your Firefox profile cannot be loaded. It may be missing or inaccessible". I already tried uninstalling with Revo uninstaller and then reinstalling again. Also tried manually deleting the profiles.ini file, trying and create a new one by putting in the run window: firefox.exe -P(it shows the error) and renaming the firefox folder to FirefoxOLD.

All Replies (13)

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Anyone else have any solutions?

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Are you able to open the Profile Manager to create a new profile?

Do you have an "Old Firefox Data" folder on the desktop indicating that the refresh feature in Firefox has been used to create a new profile?

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cor-el said

Are you able to open the Profile Manager to create a new profile? Do you have an "Old Firefox Data" folder on the desktop indicating that the refresh feature in Firefox has been used to create a new profile?


When I try to enter the window to create a new profile by running firefox.exe -P in the run window I get the same error I get when trying to launch Firefox

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Getting that same error message could indicate that Firefox is already running.

Did you try to reboot the computer to see if that has effect?

You may have to boot the computer in Windows Safe mode with network support in case security software is causing problems.

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cor-el said

Getting that same error message could indicate that Firefox is already running. Did you try to reboot the computer to see if that has effect? You may have to boot the computer in Windows Safe mode with network support in case security software is causing problems.

(Sorry for late reply)

Yeah it doesn't happen in Safe mode! But how do I make it work while not? Even with Malwarebytes disabled it still shows the error message

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Now that I try it, I can run it if I choose to run it as administrator, is this a security risk?

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Yes, running Firefox as administrator is a security risk and you shouldn't do this.

This usually means that there are permissions issues and you can try to remove the Mozilla folder in both locations.

Location used for the main profile that keeps your personal data in "AppData\Roaming" (Root Directory on about:profiles).

  • C:\Users\<user>\AppData\Roaming\Mozilla\Firefox\Profiles\<profile>\

Location used for the disk cache and other temporary files in "AppData\Local" (Local Directory on about:profiles).

  • C:\Users\<user>\AppData\Local\Mozilla\Firefox\Profiles\<profile>\

"AppData" (XP: Application Data; Mac: ~/Library; Linux: ~/.mozilla) is a hidden folder.

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cor-el said

Yes, running Firefox as administrator is a security risk and you shouldn't do this. This usually means that there are permissions issues and you can try to remove the Mozilla folder in both locations. Location used for the main profile that keeps your personal data in "AppData\Roaming" (Root Directory on about:profiles).
  • C:\Users\<user>\AppData\Roaming\Mozilla\Firefox\Profiles\<profile>\
Location used for the disk cache and other temporary files in "AppData\Local" (Local Directory on about:profiles).
  • C:\Users\<user>\AppData\Local\Mozilla\Firefox\Profiles\<profile>\
"AppData" (XP: Application Data; Mac: ~/Library; Linux: ~/.mozilla) is a hidden folder.

Unfortunately even when I delete the profiles in both locations I still get the error

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Try a clean reinstall as a normal user.


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 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.


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cor-el said

Try a clean reinstall as a normal user. 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 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.

Woo hoo! It worked THANK YOU! I verified the uninstall with Revo uninstaller and it all went perfectly! I can now launch is normally! Thank you have a good day!!

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You're welcome and thanks for confirming that a clean reinstall worked.