I just had this issue where when I attempt to install Viveport, it gets to the Preparing stage for 1-3 seconds before the whole client crashes.
But I found a fix that worked for me and hopefully it can work for you too.
Step 1. Go to your Temp folder via C Drive > User > AppData > Local > Temp
Step 2. Find everything that has to deal with HTC or Vive and delete it from that folder. It's going to be a long list of files with a bunch of numbers/ect so scroll down until you find the files.
Step 3. After deleting every HTC and Vive file within that folder, then attempt