I closed Firefox before the upgrade (and it's set to save and reload tabs from previous session). After upgrading my tabs didn't open and Firefox appeared to start a new session. I couldn't restore a previous session (option was greyed out), so I had to manually go to each website and reload all the tabs I had open before the Windows upgrade. I went to "about:sync tabs" and it lists the tabs I had open from before the upgrade. I checked on a different computer and both sessions (from before and after the Windows upgrade) are listed with the exact same computer name. Is there any way to delete the old W8.1 session's set of tabs since I've already opened them and it's really just the same computer, but with an upgraded OS?