Every now and then our Exchange 2013 server (running on Windows 2008R2) will reboot during office hours, typically in the early afternoon (say, somewhere between 15:00 and 16:00) - apparently because the server thinks it wouldn't hurt anybody because nobody is really logged in. The reboots are always related to the server installing new upgrades automatically and users are annoyed because their Outlook makes problems (if they are lucky, it simply reconnects after a few minutes, but if they were in the middle of composing a longer mail the only way to save their work is by copy-pasting all to an empty Word doc, say, and restart Outlook).
The update settings are as follows:
- install automatically (recommended)
- install daily at 06:00
So even if an update process should somehow take a whole hour, the reboot that might be necessary should happen at 07:00 in the morning and not nine to ten hours later, shouldn't it?
I would like to keep the update process as admin-friendly as possible, i.e., without the need to manually install updates off-hours or to manually schedule a reboot.
Q1: Why can it happen that the automatic reboot (always?) happens so many hours after the scheduled update installation time?
Q2: Is there any way to gobally prevent automatic reboots during office hours, i.e., to automatically delay an auto-reboot scheduled for between 08:00 and 18:00 to happen at 23:00 instead?
You can configure automatic Windows Updates, and delays for rebooting the system after updates using GPO rules.
You can find more info in this documentation: https://docs.microsoft.com/en-us/windows-server/administration/windows-server-update-services/deploy/4-configure-group-policy-settings-for-automatic-updates