If you firefox uses tabs it will always leave at least one open. If you want to remove the last open webpage open an untitled tab then close the webpage tab. If it is not the final and last remaining tab that is causing a problem is it often the same one is so * is it something you are deliberately opening ? * what is it ? * and what is it doing / using ? Have a look at *[[Safe Mode]] * [[Basic troubleshooting]] * [[Firefox hangs]]