I have not found out what is specifically causing this, but it is repeating at least four times daily during work. My work PC (used for testing) will just stop functioning, but the mouse continues to be visible and moveable. The network and backend will continue working because I can use Restart-Computer from a remote server to reboot my PC. Other than that, everything is inaccessible on my PC until rebooted. There is nothing I have found common to the issue. Apps open all the time are Outlook, Teams and Edge/Chrome.