See: https://support.mozilla.com/en-US/kb/uninstalling%20Firefox *the page detects your OS automatically with the browser used to open the page. *To get the correct instructions: **If you are un-installing from an OSX system, go to the page with a system using OSX. **Open the page with a Windows system if un-installing from a Windows system. Un-install your personal information also (bookmarks, passwords, etc.) as mentioned on that page.