Hi Dan, sorry to hear about this problem. Are these "normal" tabs or "pinned" tabs? If they are normal tabs, you need to set Firefox to Restore Previous Session on the Settings page. If they are pinned tabs, and they are in a window that is open at the time you quit Firefox, then they should be restored automatically. In either cases, you could try a manual session restore from the menu -- * "3-bar" menu button > History > Restore Previous Session * (menu bar) History > Restore Previous Session If they are missing or grayed, check either: * "3-bar" menu button > History > Recently Closed Windows * "Library" toolbar button > History > Recently Closed Windows * (menu bar) History > Recently Closed Windows Any luck there? ---- If Firefox doesn't recognize that it has a session to restore, it's possible there is a problem with saving/restoring the session history file(s). Here's how to diagnose that in more detail: '''(1) Make sure Firefox isn't erasing history''' On the Settings page, Privacy & Security panel, in the History section: The main selector has three positions. If yours reads Firefox will: Never remember history That indicates automatic private browsing mode, so no cookies or other site data, or history, can be retained. So that setting would be incompatible with restoring the previous session. ''With the selector set to'' Firefox will: Use custom settings for history review these two items: [_] Always use private browsing mode => must not be checked [_] Clear history when Firefox closes => must not be checked, or click the Settings button to the right and make sure that "Browsing & Download History" is NOT checked Can we rule out those incompatible settings as the source of the problem? '''(2) Is any external software possibly "cleaning" your browser data?''' Advanced SystemCare and CCleaner can be set to remove browser history. We would want to rule those out. '''(3) Are files getting updated properly?''' Details on this to follow if the problem continues.