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FF won't run

  • 4 replies
  • 1 has this problem
  • Last reply by cathc

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I get this error message when try to open Firefox "Your Firefox profile cannot be loaded. It may be missing or inaccessible" When I try to create a new profile I get "An unexpected error has prevented your changes from being saved" I have deleted the profiles.ini file I have reinstalled Firefox several times. I can't refresh Firefox because it won't open. If I try to start it while pressing the Alt key I still get the error message above. I'm running Windows 8.1 I have had to download chrome to post on here. I just want my Firefox back!

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You can check the read/write permissions and owner for both location Firefox uses for the profile folder. Also make sure that profiles.ini and installs.ini aren't read-only.

Firefox uses two locations for the Firefox profile folder. One location for your personal data (e.g. bookmarks) and another location for temporary files like the disk cache.

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

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

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

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


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Hi Cor-el,

Thanks for getting back to me. I deleted the profile.ini file from


so I'm not able to check read/write permissions and owner

I couldn't see a file in


There are folders that appear to be profile folders. Most of them have "default" in the folder name but I guess they can't all be default profiles, but most are empty folders. The one that isn't doesn't contain a profile.ini file. Some of the folders do have dates that indicate they've been modified recently. I don't know if that's relevant.

Is there any more information I can give you that would help?


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There is only one profiles.ini file as this file stores the extensions registry data. If you create a new profile then this profile needs to be registered in profiles.ini and if this fails as you question seems to suggest then Firefox won't start.

The profile location in "AppData\Local" is only used to store temporary files like the disk cache and phishing protection data (Google Safe Browsing).

You can try to rename the Mozilla folder in "Mozilla\Firefox\Profiles\" path in both locations (AppData\Roaming and AppData\Local) to "MozillaOLD" to see whether this allows to create a new profile structure.


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Thanks Cor-el,

There isn't a profile.ini file because I deleted it. I've since done a forced removal of all FF data and reinstalled from scratch. It seems to be working now. It does mean I've lost my bookmarks but I had to do something. Chrome was maqking my comp crash all the time.

i appreciate you taking the time to help.



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