In today's episode of Will hates computers and vice-versa: Because Microsoft recognized that pretty much everybody logs into Windows as an admin user, they created a new feature called Administrator protection, which adds extra protections for those who use their computer in such a YOLO manner. The consequence of this feature being enabled on systems where you don't log in as an admin user is that an elevated process running as this admin user will have a different %USERPROFILE% value than expected. e.g. if I have an admin user called admin, this elevated process will use C:\Users\ADMIN_admin instead of C:\Users\admin as usual. If this isn't your first time using Windows, you probably have apps that store things in the admin user's home directory. The real-world consequence of Administrator Protection suddenly being enabled is that any app that's looking for a file in the admin user's home directory will no longer find it. The profile directory that's prefixed with ADMIN_ starts as a clean slate with basically nothing in it. Edit It has come to my attention that I may have had Administrator Protection enabled (by way of Harden System Security) all along, but perhaps Microsoft rolled out an update recently to cause it to be actually enforced. 🤷‍♂️