UE4Editor hangs at 80% while load

I’ve downloaded and tried building the latest 4.21 branch of the UE4Editor. Unfortunately, while loading the editor it hangs at 80%. I also tried building the 4.20 branch and that does work, except after I switch to vulkan by adding the -vulkan command line parameter, it also hangs at 80%. This leads me to believe it may be vulkan related. I’m using the 390.87 NVidia drivers with a GTX 1080 and was hoping to do some development for the HTC Vive. Any suggestions?

The reason why it was hanging at 80% was because SteamVR was not running. In opengl, this was not a problem, but in vulkan it would hang. I am guessing that it detected my HMD, and was trying to initialize VR but couldn’t and was not able to handle this gracefully.