Hi again ,
I have managed to solve the issue in the most powerful computer. In this one I was using firmware 0.4.4 and VR preview wasn’t even available in UE4.8.3. I updated to 0.6.0.1 and worked.
On the less powerful computer I already had the last firmware and there’s where the black screen appears with UE4.8.3. Again, it works with 4.7.6, so I can’t imagine where the problem can be, but seems to be related to last UE4 update and system requirements.
Also tried 4.9.3 and no luck
I’ll make some more tests tomorrow.
Best