That is the Defender real time protection, loves to hog enormous amounts of CPU during any file I/O, you can disable it temporarily but it very aggressively nag

That is the Defender real time protection, loves to hog enormous amounts of CPU during any file I/O, you can disable it temporarily but it very aggressively nags you about it. However it does let you exclude specific folders and will not prevent you from doing things like excluding your entire home folder or even C:\.