You only see the reset button on the "Help > Troubleshooting Information" page if you use the profile that is marked as Default=1 in the profiles.ini file. If you do not have the "Reset" button then either use the Profile Manager to create a new profile or use the Profile Manager to start with the current default profile to get the Reset button in Firefox. What problems do you have that you want to reset Firefox? ----- Create a new profile as a test to check if your current profile is causing the problem. 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 If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems. *http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox