If you have found that you need to sign in to your Microsoft account the next time you restart your computer then you have fallen for this trickery as well.
The first thing to note when you go to download an app from the Microsoft store, which you will need to do any time you restart your computer and have not already signed in to your account is to choose SIGN IN TO JUST THIS APP INSTEAD (see image below)
If you have already screwed up and find that you now have to sign in to your Microsoft account upon restart of your computer then you will want to follow these instructions to change this.