Got it working... Had to copy the files from my computer where it's working and dumped them on the one it wasn't working. Ran the Viveport installer a few times, rebooted a few times, etc etc, and for reasons I can't explain it finally started to work. Viveport used to just work, but if this is the direction it's going, the future is grim.
A recent update seems to have completely broken Viveport Desktop. Viveport stopped launching entirely and couldn't get it running. This happened on 2 completely different computers with different headsets. I managed to get one working and installed after several problems with the updater failing. On the other, I uninstalled Viveport, but now it refuses to actually reinstall. First it says there's no drive space... Pretty sure 320gb of free space is more than enough lol! Click TRY AGAIN and it seems to proceed. The ViveportSetup says it installs and completes, but then nothing. No files were actually installed. Then for whatever strange reason the Windows thing that asks what program you want to use to open a file pops up... Was fine a month or two ago... Something changed since then, and it's not on my end because again, 2 completely different PCs having this issue.