Microsoft doesn't give you much of choice when it comes to installing Windows 10 updates, even when it can be incredibly disruptive. Fortunately, there's now a way to block updates, permanently or temporarily, using a new tool called "StopUpdates10".
Created by "Alex Nightwatcher", the app makes changes to the registry to not only stop Windows updates and "forced upgrades", but to squelch update notifications as well.
The tool's not very complicated to use: fire it up, click "Stop Windows Updates!" and you're done. The tweak is reversible, so when you do want to update, you can still do so.
You can even streamline activation / deactivation via the command line:
The first switch disables updates, while the second turns them back on.