Hello, It is most likely that Firefox is set to clear data upon closing. Here's how to disable it : Search '''about:preferences#privacy''' in the address bar. Under History, set it to "Remember history" or, if using custom settings, uncheck "Clear history when Firefox closes" .If you want to keep that setting on, make sure Cookies and Active Logins are unchecked. If it doesn't work, it is possible that you are private browsing mode. Search '''about:preferences#privacy''' in the adress bar, scroll to history. Then, uncheck Always use Private Browsing mode. If the tabs still close, even after the previous ones worked, Search '''about:preferences#general''', then under startup, check Open previous windows and tabs. For cookies, Search '''about:preferences#privacy''' in the adress bar, and scroll to cookies and site data Then, make sure '''Delete cookies and site data when Firefox is closed''' is unchecked