I have more or less learned to live with defender, it does have it's value.
It's knee jerk to disable real-time scanning. Defender has stop playing games and restoring it to "on" at random intervals. As soon as it is restored it will gobble up any naked crack or keygen. The ignore thing doesn't work if you move the file to another location. I just keep all the sensitive stuff Rar'd up encrypted and pass protected to keep defender from snooping which it will do.
I also have a paid subscription to an A/V-spyware program that suits my needs and they aren't paying me to endorse them. Keep in mind, there is no one-size fits all A/V solution, if there is one program worth a paid subscription, a trustworthy A/V is it. On top of everything else, two things are true. The most powerful A/V program is between your ears. Frigging Internet security is a whack a mole game. There are no set rules and they are constantly changing. Windows and to a lessor extent Internet communication programs change all the time and create new issues.