After opening Firefox you get a pop-up error, it says; “Your Firefox profile cannot be loaded. It may be missing or inaccessible.” From my experience, the best way to fix the Mozilla Firefox Profile Error is to press the Windows Key + R together. Type or copy and paste “%APPDATA%\Mozilla\Firefox” into the Run box and hit enter. Delete your profiles.ini file. Firefox will automatically create a new profiles.ini file on the next restart and a new default profile will be created. This fix may or may not work for you, but this is what worked for me. If you need help post your questions / comments below or email us here.