To Country Bumpkin, as per earlier in this thread, the issue is size dependent. 32Gb works, 64Gb works, 128Gb does not, 200Gb does not on 500Gb etc.
All are picked up without issue by Windows 10.
I installed JRiver 22 on Windows 7 64 Bit Enterprise edition, I have the same issue there. I am pretty sure its a JRiver issue and not Microsoft operating system related.
I have in the interim bought a lifetime licence on another player, I updated that player to my library, it sees JRiver play lists. It sees all my USB and CF drives regardless of capacity. So I have updated my drives with that as I have a long work related road trip starting tomorrow morning.
This now begs the question why do I need both if all I want is to play media, one product has issues with external devices, the other does not. Both support lossless audio, Wasapi, Asio etc etc. Both are supposed to play bit perfect?