Tabs from previous session are erased

Sorry to hear about this problem. Probably you've looked for them, but are either of these are available (not hidden or grayed out): * "3-bar" menu button > History > Restore Previous Session * History menu (Alt+S) > Restore Previous Session If they are missing or grayed, check either: * "3-bar" menu button > History > Recently Closed Windows * History menu (Alt+S) > Recently Closed Windows Can you recover any closed windows there? ---- One factor in what windows or how many windows are restored is how Firefox is shut down. If Firefox is closed one window at a time, only the last closed windows will be restored automatically, and the last three of the others will be on the Recently Closed Windows list. For that reason, long time users will recommend to shut down Firefox using the menu. Either: * "3-bar" menu button > Exit * File menu (Alt+F) > Exit Letting Windows shut down Firefox is risky because as far as I know, it doesn't integrate with the Exit command. ---- Finally, we should confirm that your Firefox is not set to delete browsing history when it closes, since tabs are part of browsing history. You can check here: Settings > Privacy and security > History If you have: * Remember history => this is compatible with restoring your session * Never remember history => session restore is impossible * Customize history => need to check the specific settings ''Customize History options'' * You need a checkmark for "Remember browsing and download history" * If "Clear history when Firefox closes" is selected, open that feature's Settings and make sure there is NOT a checkmark for "Browsing & download history" here