So, like a dummy, since sierra is working great on my 2012 rMBP, I go ahead and install it on my home server (2012 mac mini, 16gb ram, 512 ssd samsung 840pro).... I also have an external enclosure attached by usb 3 with 4 4tb drives and an internal 1gb HDD. and boom everything goes to hell. Now it's true I run a lot of stuff on the server, and maybe I should have waited... but nothing is mission critical here, and I have all my important documents and media backed up... anyway, every time I launch safari, or safari is launched by another app (Plex, sickrage, couchpotato...) BOOM screen flashes and I see a login screen. it happens every damn time... So I already re-installed sierra in place from the recovery boot mode (kept existing settings). I am looking for some ideas before I do a full wipe, and have to reconfigure all my server crap... thanks for any input other than "Hope you have a backup! LMFAO LOL ROFL" *addtional info* it seems to also happen when I try to take any app fullscreen.