I have a 2017 iMac, and have recently updated the OS to Monterrey, version 12.5. I believe I was on Big Sur before that. Now, although when I start my iMac's Shut Down feature, I specify that current open windows shd be reopened, when I start up the Mac again, the Shut Down function asks me if it is OK to close the open Firefox tabs. If I remember correctly, doing that results in all those tabs being lost, and none of them appear when I reopen the Mac. Under some circumstances that I can't remember enough to describe, the gMail windows do come up, and their contents are shown on the tabs, but are lost when I open the tabs -- instead each window changes to request a new login to gMail. The only way I can get the old windows to be retained is to not agree that the tabs be closed and to do a Force Quit on Firefox. I am using a very old version of Firefox (02.2 G4bit (? I think)), but under Big Sur, the exact windows were retained. Here are my "About This Mac," and "About Firefox" displays. I don't know how to find similar info on gMail. /moved thread from Firefox for <b>iOS</b> (for iPhone/iPad) to Firefox section as you have <b>macOS</b>.