Argh, you’re kidding me. Did the Realtek HD Audio Drivers 18.104.22.16845 really just copy everything it found in the folder with the setup file over to the Program Files directory? Not the files in the executable .zip file, not the files in a list, no, everything it could get its grubby digital hands on. So a quick driver update ended up copying 40 GB of crud between two hard drives. Reminder to self: clean out the TEMP folder more often!