@
stumped - AFAIK Defender and MWB take two different approaches to Ransomware protection, and both can peacefully coexist - well on my rigs they can
Since I switched to Win7 in late 2008 (couldn't wait to get off XP) I can't recall having any MS update related problems. Prior to that, problems such as you describe were legion of course.
I've also been running MS Security Essentials/Defender together with MWB Pro since then. IIRC Avast was the last of many AVs I used on XP - they were all nightmares. What I like about my current combination is that I hardly know they are there, both from an interrupt and a performance perspective. And, apart from an obscure weather gadget, I have never had to explicitly exclude any software or data from either of them.
Good grief I just realised I've been running MS AV and MWB together for more than a decade.
BR