This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

Firefox crashes

  • 1 reply
  • 1 has this problem
  • 3 views
  • Last reply by cor-el

more options

My system wont open firefox. it says that my profile (JSON) is missing or inaccessible

My system wont open firefox. it says that my profile (JSON) is missing or inaccessible

All Replies (1)

more options

There might be a problem with permissions/ownership of involved folders/files preventing access. You can check for problems with the profiles.ini file that registers profiles.

See:


You can try these steps:

You can find the profiles.ini file in this hidden location:

  • Windows: %AppData%\Mozilla\Firefox\
    C:\Users\<user>\AppData\Roaming\Mozilla\Firefox\
  • Mac: ~/Library/Application Support/Firefox/
  • Linux: ~/.mozilla/firefox/

You can recover an orphaned profile via these steps:

See "Profile was moved or renamed":

Note that you should never use "Choose Folder" to specify a folder that already contains files that do not belong to Firefox. Only use "Choose Folder" to recover an profile that isn't listed in the Profile Manager.

If this didn't work then check the read/write permissions and owner or remove the Mozilla/Firefox folder in both main/root and cache locations.

Location of the cache files.

  • Windows: C:\Users\<user>\AppData\Local\Mozilla\Firefox\Profiles\<profile>\
  • Mac: ~/Library/Caches/Firefox/Profiles/
  • Linux:~/.cache/mozilla/firefox/

You can check if you have an "Old Firefox Data" folder on the desktop in case the Refresh feature in Firefox has been used and a new profile has been created.