Since build 1607 of Windows 10, it automatically restarts after updates, regardless of your wishes or unsaved documents. And since I do most of my work on a Virtual Machine that runs 24/7, this is not desired behaviour (putting it mildly).
In previous builds, there were options to postpone restarts until you manually approved. Not anymore...
This article by Martin Brinkmann shows a way to fix this: http://www.ghacks.net/2016/09/20/disable-reboot-after-automatic-windows-updates/
I did not install the "Take Ownership" program; doing that manually is easy enough.
Note: This solution worked fine for a while - however, recently (June 14th 2017) Windows somehow undid the fix (all settings were set back to their old status) and restarted my VM anyway. Bugger. I've implemented the fix again, hopefully Windows will keep its dirty hands off this time...
It happened again, while multiple applications were running (Feb 14th 2018)... So I had another go at it; this time I tried the suggestions mentioned here: https://docs.microsoft.com/en-us/windows/deployment/update/waas-restart
. Fingers crossed.