I have several SBS 2011 boxes deployed and configured similarly. One of them has a very odd problem. When Windows Updates take place and an admin user is not logged in, the server will reboot upon completion of updates. When an admin user is logged in, the server does not reboot upon completion of updates, but will reboot IMMEDIATELY when the admin user logs off.
This means, if I have a remote session open during the evening when updates happen, and then connect back in during daytime hours and then log off the session, the server reboots IMMEDIATELY, causing my users to be down for about 10 minutes or so.
All of my other SBS 2011 do not reboot immediately, but rather wait until the next scheduled update time to initiate the reboot after the admin user logs off.
All of my SBS 2011 servers are WSUS servers and clients of themselves. I have compare respective Group Policy settings and everything seems to be identical between the affected server and the unaffected servers.
Does anyone know what setting could cause a server reboot immediately upon user logoff due to a pending updates reboot request?