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How do I fix Firefox not opening?

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I had two profiles, was in the process of trying to learn how to use the 2nd profile (as seen in the link below), which I still have no answer for. Somehow, maybe I held down SHIFT for too long and clicked on something by accident, idk, but somehow, I ended up REFRESHING the 2nd profile, causing it to delete everything I had done with it, and it backed up the old profile onto my desktop in the process. I figured I could just simply delete the new profile folder it had created and put back my old profile in the profile folder, but now, Firefox will not open at all, saying "Your Firefox profile cannot be loaded. It may be missing or inaccessible." How do I get it to recognize the profile folders again? OMG, I'm using Microsoft Edge, please, get me out of this!

https://support.mozilla.org/en-US/questions/1479231

I had two profiles, was in the process of trying to learn how to use the 2nd profile (as seen in the link below), which I still have no answer for. Somehow, maybe I held down SHIFT for too long and clicked on something by accident, idk, but somehow, I ended up REFRESHING the 2nd profile, causing it to delete everything I had done with it, and it backed up the old profile onto my desktop in the process. I figured I could just simply delete the new profile folder it had created and put back my old profile in the profile folder, but now, Firefox will not open at all, saying "Your Firefox profile cannot be loaded. It may be missing or inaccessible." How do I get it to recognize the profile folders again? OMG, I'm using Microsoft Edge, please, get me out of this! https://support.mozilla.org/en-US/questions/1479231

Chosen solution

The reason for this problem is:

In the folder at

C:\Users\<username>\AppData\Roaming\Mozilla\Firefox

there are two .ini files which Firefox uses as an index to locate your profile folders. When you remove the default profile folder, Firefox complains about not being able to find it because it is still listed as default in those files (installs.ini, profiles.ini).

What you need to do now

Use a plain text editor to change the profile paths in installs.ini and profiles.ini from the deleted folder to the one you put back into the Profiles folder.

What does that look like -- hypothetical paths in installs.ini

BEFORE (matches the removed folder):

Default=Profiles/abcd1234.default-release-345713438241

AFTER (matches the current folder):

Default=Profiles/7654zwxy.default-release

Do you see what I did there?

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All Replies (2)

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Chosen Solution

The reason for this problem is:

In the folder at

C:\Users\<username>\AppData\Roaming\Mozilla\Firefox

there are two .ini files which Firefox uses as an index to locate your profile folders. When you remove the default profile folder, Firefox complains about not being able to find it because it is still listed as default in those files (installs.ini, profiles.ini).

What you need to do now

Use a plain text editor to change the profile paths in installs.ini and profiles.ini from the deleted folder to the one you put back into the Profiles folder.

What does that look like -- hypothetical paths in installs.ini

BEFORE (matches the removed folder):

Default=Profiles/abcd1234.default-release-345713438241

AFTER (matches the current folder):

Default=Profiles/7654zwxy.default-release

Do you see what I did there?

Helpful?

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By the way, holding shift when launching Firefox would typically trigger display of a dialog that offers the options to either Open Firefox in troubleshoot mode or Refresh the program. I think you used Refresh. See: Refresh Firefox - reset add-ons and settings.

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