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Old Firefox Profile not working in Windows 10?

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Hi all - upgraded to Win10 this morning from Win7. Firefox was working fine before.

My old Firefox Profile was always saved to Program Files/Mozilla Firefox/Profile.

Upon finally getting into Win10's desktop, went to start Firefox and get a "Firefox is already running, but not responding. The old process must be closed to open a new window." error. I click Close Firefox, then get a "Your Firefox Profile cannot be loaded. It may be missing or inaccessible." message. Again, it was working perfectly before the Win10 upgrade.

I tried creating a second profile and opening Firefox with that - THAT new profile works fine. OK, go back to the Profile Manager and try signing in with the old profile again: "Firefox cannot use the profile "Profile" because it is in use."

What the heck is going on? :S Is my profile in use, or is it corrupted or what? I don't want to lose my bookmarks, settings and saved passwords as my last backup of them was from a few months ago....any ideas what I can check for???

I've already deleted the 'parent.lock' file, so that hasn't seemed to help....

Thanks for any suggestions!

Hi all - upgraded to Win10 this morning from Win7. Firefox was working fine before. My old Firefox Profile was always saved to Program Files/Mozilla Firefox/Profile. Upon finally getting into Win10's desktop, went to start Firefox and get a "Firefox is already running, but not responding. The old process must be closed to open a new window." error. I click Close Firefox, then get a "Your Firefox Profile cannot be loaded. It may be missing or inaccessible." message. Again, it was working perfectly before the Win10 upgrade. I tried creating a second profile and opening Firefox with that - THAT new profile works fine. OK, go back to the Profile Manager and try signing in with the old profile again: "Firefox cannot use the profile "Profile" because it is in use." What the heck is going on? :S Is my profile in use, or is it corrupted or what? I don't want to lose my bookmarks, settings and saved passwords as my last backup of them was from a few months ago....any ideas what I can check for??? I've already deleted the 'parent.lock' file, so that hasn't seemed to help.... Thanks for any suggestions!

Athraithe ag Darkstrike ar

Réiteach roghnaithe

Sorry, but Program Files/Mozilla Firefox/Profile is not the location of the user's Profile, which are located in C:/Users/ path and further down thru 5 or 6 levels of folders.

Use the Help > Troubleshooting Information - > Profile Folder -- Show Folder button to see where your Profile is located. Then attempt to verify that your old folder is located similarly.

You can copy files from the old Profile to the new Profile, using this support article as a guide. https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile

Be careful as to which files you copy over or you're liable to end up with the same problem all over again. IMO, the one file not to copy over is a prefs.js file.

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Réiteach Roghnaithe

Sorry, but Program Files/Mozilla Firefox/Profile is not the location of the user's Profile, which are located in C:/Users/ path and further down thru 5 or 6 levels of folders.

Use the Help > Troubleshooting Information - > Profile Folder -- Show Folder button to see where your Profile is located. Then attempt to verify that your old folder is located similarly.

You can copy files from the old Profile to the new Profile, using this support article as a guide. https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile

Be careful as to which files you copy over or you're liable to end up with the same problem all over again. IMO, the one file not to copy over is a prefs.js file.

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That's the thing, it IS the location of my profile, because back in the day, that's the directory I told the Profile Manager to save my profile to.

I did manage to copy my data to a new profile though, so all is well! :)

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Darkstrike said

That's the thing, it IS the location of my profile, because back in the day, that's the directory I told the Profile Manager to save my profile to.

Sorry, I should have thought to mention that as a possibility for the Profile being there.

I glad that I helped get your problem solved.