You need to have a FULL understanding of the UHD decrypting requirements. Not as simple as popping in the disc on any drive and copying. These requirements have been discussed in detail over the past several months in this forum and are there for a reason.
Gotta do a bit of leg work on your end and read up a bit.
1. Start here:
http://www.makemkv.com/forum2/viewtopic ... 12&t=16883
2. Once you understand COMPLETELY what is being discussed in that FAQ, ask yourself, do I meet one of the EXACT requirements for decrypting these UHD discs? If so, post in detail what you are experiencing and your setup. (E.g. drive model, firmware/SVC version, exact error as returned by MakeMKV, 100% positive hash key file is in CORRECT location?, etc). Gotta help us help you.