Try to delete the profiles.ini file to force Firefox to create a new default profile.

• http://kb.mozillazine.org/profiles.ini_file
• http://kb.mozillazine.org/Profile_folder_-_Firefox

Can't you launch the Profile Manager by adding a space and the -P switch to the command line?

See "Creating a profile":

• https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues
• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

I changed my ini file, all you need to fix it. Find the location C:\Users\Marian\AppData\Roaming\Mozilla\Firefos, open the ini file in notepad, then open the location C:\Users\Marian\AppData\Roaming\Mozilla\Firefox\Profiles, and see how Mozilla called a profile, may be more than one. It should be something like this rjuijto8.default. Makes your ini file should look like this   [General] StartWithLastProfile = 1

[Profile0] Name = default IsRelative = 1 Path = Profiles/rjuijto8.default

If you have more than one profile Try to change the ini file until you see that your settings.