Same issue here, I think this desktop app is supposed to be installed in the background, maybe one of those black windows that pop-up when you run the main installer.
I've been trying to manually install it from:
C:\Program Files (x86)\ViveSetup\Updater\App\PCClient
But it fails every time I try, one time it said account already exists, now it just fails.
I've removed all vive software and re-installed about 5 times now.
I'm just going to stick with SteamVR as it seems to run without issue.
M