Microsoft gave CrowdStrike unfettered access to push an update that can BSOD every Windows machine without a bypass or failsafe in place. That turned out to be a bad idea.

They have to give that access by EU ruling:

Microsoft software licensing expert Rich Gibbons said: “Microsoft has received some criticism for the fact that a third party was able to affect Windows at such a deep technical level. It’s interesting that Microsoft has pointed out the fact this stems from a 2009 EU anti-competition ruling that means Microsoft must give other security companies the same access to the Windows kernel as they have themselves.”