''BreezyOhio [[#question-1212491|said]]'' <blockquote> I normally shut down FF (almost always in single window mode) by clicking the X button. Do I need to exit by going into the menu and selecting exit instead? </blockquote> The '''X''' closes the window. But sometimes Firefox still remains running. Some users were told to use the menu '''Exit''' and got better results. <blockquote> When this happens I have to go back into my history and reload tabs that I know I wanted to keep up. </blockquote> What you could do is create a new bookmarks folder and place those here. <blockquote> I had created a sync account a month or so ago but it screwed up my bookmarks royally so I shut that down but did not close the account. Can that contribute? </blockquote> If sync is shut down it should cause no problems. <blockquote> Also I thought that the new FF backed up multiple sessions of open tabs in case they need to be restored but I cannot find anything like that anywhere. </blockquote> That information is stored in the '''sessionstore''' files. You may have corrupt '''sessionstore''' [v56] '''sessionstore.jsonlz4''' file(s). Delete all '''sessionstore*''' files and the '''sessionstore-backups''' folder. Type '''about:support'''<enter> in the address bar. Under the page logo on the left side, you will see '''Application Basics. ''' Under this find '''Profile Folder. ''' To its right press the button '''Show Folder. ''' This will open your file browser to the current Firefox profile. Now '''Close Firefox. ''' Locate the above file. Then rename or delete it. Restart Firefox.