txt, so you may only see a file name User without file extension. Windows hides some file extensions by default.Īmong them.

Help > Troubleshooting Information > Profile Directory: Show Folder (Linux: Open Directory Mac: Show in Finder).

You can use this button to go to the current Firefox profile folder: You can delete the user.js file if you didn't create this file yourself. The user.js file is read each time Firefox is started and initializes preferences to the value specified in this file, so preferences set via user.js can only be changed temporarily for the current session. You can check its content with a plain text editor (right-click: 'Open with' do not double-click).

You can check if you have a user.js file in the Firefox profile folder that sets the _session_once pref to true. The user.js file will only be present if you or other software has created this file and normally won't be present. Your System Details list shows that you have a user.js file in the profile folder to initialize prefs each time Firefox starts.

Firefox focus tabs