Despite a good deal of negative feedback from users, WindowServer is a legitimate macOS process that plays an important role in enabling proper manifestation of graphical elements on the display. It is geared toward dynamic reflection of app windows and the embedded visual objects so that the user experience is seamless. Ideally, when you notice it running on your Mac, that’s perfectly normal. In some situations, though, WindowServer may get out of hand by gobbling up most of the processor and memory resources. This likelihood of this drag increases when a user connects an external display to their Mac, especially one that supports 4K resolution. The problem may also be security-flavored: crudely made malware, crypto miners, and adware often impersonate benign system services and are to blame for slowing down a system to a crawl.