¡Hola!

Please see How to run Firefox when your profile is missing or inaccessible.

Let us know if this solves your question.

¡Gracias!

Dear Alex First of all thank you for your quick response , I tried to find a solution with the task manager but there are no firefox processes on the list in order to end them . Could you please provide me some other solution because any other solution that the link provides cannot help me at least to my knowledge . Thanks in advance Babis

You need to locate the profiles.ini file and delete this file or use the Profile Manager to create a new profile.

You can use one of these to make Firefox create a new default profile or recover an existing profile:

• Delete the profiles.ini file to make Firefox create a new (default) profile
• Use the Profile Manager to create a new profile
  If you still have an existing profile then click "Choose Folder" in the Profile Manager and browse to the location of a lost profile to recover this profile
  https://support.mozilla.org/kb/Managing+profiles

You should 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/

If clearing the profiles.ini file isn't working then also check the 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 also try to rename/delete the Mozilla\Firefox folder in both above mentioned locations (main, cache).

• http://kb.mozillazine.org/Profile_Manager
• https://support.mozilla.org/kb/Managing+profiles
• http://kb.mozillazine.org/Profile_folder_-_Firefox