Mostly unrelated other than involving Defender and malware.
Just two days ago I opened Defender to update and run a full scan (as I usually do once a week to supplement the normal automated quick scans and the active scanning), anyone care to guess what happened when the update finished downloading?
Defender marked its own update as "Severe - Trojan:Win32/Vagger!rfn" and threw it into quarantine.
Rather than faff around I just formatted and reinstalled, I keep regular backups so nothing was lost and all was again well. To many this may seem an extreme reaction, but without knowing if the update was compromised or if Defender itself was compromised and hence quarantining any updates which might kill the infection I considered it the best course of action. Either way I am unimpressed with the security of Defender.