I've seen that option but never tried it myself (screenshot attached).

Does it help to launch a new window (Ctrl+N, or on Mac, Command+N) and close the window(s) with your own tabs BEFORE signing out and clearing history so that only a single new tab is open? I ask that because Firefox will normally create a session history file with your open tabs (and recently closed windows and tabs) as you browse and during a normal shutdown.

Since those processes take place after you sign out and clear history, it usually would include all the open tabs. However, if you closed all your own tabs before clearing data and it is still possible to restore your session, hmm, that sounds like a bug.

I've seen that option but never tried it myself (screenshot attached).

Does it help to launch a new window (Ctrl+N, or on Mac, Command+N) and close the window(s) with your own tabs BEFORE signing out and clearing history so that only a single new tab is open? I ask that because Firefox will normally create a session history file with your open tabs (and recently closed windows and tabs) as you browse and during a normal shutdown.

Since those processes take place after you sign out and clear history, it usually would include all the open tabs. However, if you closed all your own tabs before clearing data and it is still possible to restore your session, hmm, that sounds like a bug.

I use this option all the time. I daily login to the work PC and in the end of the day signing out and erasing everything. You can open the new window, yes, but that wasn't the case earlier. It erased everything and didn't open the windows on the firefox relaunch. And even if I open new window it stil keep my quick buttins on the empty page after I log out. I may be wrong but previously it erased everything that related to my account.