I’ve had an issue when updating Rhinoceros this morning.
At the middle of its installation process, the update software told it had “not sufficient privileges” to actually install something in C:\Program Files… The progress bar stalled, so I’ve hit the close button at the top of the install window (I already knew this was a bad idea but I was in a hurry).
Then the same alert window about privileges popped-up several times again. I checked in the windows task manager and the installer software was still active, though no install window was showing up.
After I killed that process, I found the Rhino WIP\System folder empty and inaccessible (I had no right to open it).
I hope it’s just me, or there is something you guys could do to make the update process less painful 
Cheers