I've figured out what caused my Windows 10 Taskbar to freeze after switching users in Windows 10. My new Razer Deathadder V2 is causing the problems. I have no idea how. It has the latest drivers installed, latest firmware, even the software is up to date. I've tried using it on another PC and the same problem occurs, which means it's not just my PC. I've tried using the workaround someone posted in the official Razer forum. (https://insider.razer.com/index.php?threads/task-start-bar-delay-workaround.72732/#post-741439) I've followed the steps there and accidentally broke my headset (didn't connect to windows and stuff; I fixed it though). So overall, I have no idea how a USB device can technically crash Windows.