Unreal engine requires SteamVR to also be running and connected to the headset (before you open your project) as it uses the steamVR API to launch VR Preview. Otherwise VR Preview will be greyed out like it is for you.
Unreal engine requires SteamVR to also be running and connected to the headset (before you open your project) as it uses the steamVR API to launch VR Preview. Otherwise VR Preview will be greyed out like it is for you.