Windows 10 won't let you delay or prevent Windows automatic updates from installing.

[SvennoJ]

By you can delay the reboot, do they mean the reoccurring 15 minute nagging to reboot now or later, and if you miss it once, tough luck. I have lost work too that way, and have come back to an empty desktop the next morning. (I usually have tons of browser windows open, folders, image programs etc.) Automatic updates are turned off. (Of course now when I decide to reboot it takes forever to get through the backlog of updates :/)

I'll wait, there are bound to be a lot of updates in the beginning. Hopefully at the end of the free upgrade year it will have settled down a bit.