It's funny but after tweaking Win 8 years ago, I have never been able to enable Win Defender again. It simply refuses to start, go figure. It's garbage on Win 8 anyway, so I don't care.
Same here on 8.1-frankly not needed whatsoever IMO. With much improved and more effective third party security programs of the caliber they've reached since Win 10's first introduction, that particular tie-in is there, just inert (as in non-essential)
There's a free program that came with my computer. It's called Microsoft Works. Now there's an Oxymoron for you!
At one stage I couldn't update MSE when I ran 7. I switched to Panda until I dropped Microsoft completely. All in all MSE was a pretty good AV. I don't need an AV now of course.