Re: Worrying
Where do you live? In Italy my machines at home, which gets updates directly from MS, usually takes a few minutes (usually less than ten, OK, SSDs disk help) to check and update, and that's over an old 7 Mb/s ADSL. The WSUS server at the Office sync flawlessly at night.
Never saw an automatic reboot which cannot be delayed when a user is logged, especially before all updates have been downloaded and installed - but check your Windows Update policies. If WU is configured to automatically update, and no user is logged, it will reboot automatically (that's how you updated unattended systems). Error codes have a meaning but MS made them cryptic, it may take time to understand what they really mean.
Sometimes Windows may reboot automatically when it processes some specific updates after the first reboot, but it happens before the logon screen.
You would need to understand where the issue really is, the network traffic, or the system itself (if not both). Because it was your previous situation to be "wrong".
Biting the hand that feeds IT
