I worked with a clinet this morning who’s backup didnt work the last 3 days. I checked the event viewer showed that the PC downloaded windows updates and automicly installed them. it also required a reboot and it said that the PC was going to reboot in 5 minutes and it did. the backup was scheduled at 6:00 am so it was unable to backup becasue it was not logged in. this could also cause problems with polling as well, so keep and eye out for this. you can configure it so it will download updated but allow you to install them under START>settings>control pannel> security center> manage security settings for automatic updates

In answer book under PC REBOOTS, Windows automatic updates