See what I wrote earlier about the "official" software failing catastrophically
. Basically, the Movie Industry was relying on a feature of Intel CPUs that would allow them to keep secrets from you when running their code on your Windows(-only!) (Intel) PC.And then some Really Clever People discovered that they could always poke holes in this feature that were big enough for them to peek through...
Which lead Intel to abandon this feature in their future CPUs.
Which in turn left "official UHD player software" up a certain creek without a paddle!
What all this means for the future is not yet clear, because the only official UHD solutions left now are dedicated 4K BluRay players. And after their firmware updates blocked LibreDrive, Pioneer's range of (very nice!) USB3 drives is only usable for playing standard BluRays, and for users burning their own BDXL disks.