The Terminator problem

[maiks]

Hi, I copied the complete content of an Blu-ray to the hard drive and tried to make an MKV of it:
MakeMKV v1.10.7 win(x64-release) started
Opening files on harddrive at D:/Media/Video/THE_TERMINATOR_BD
The volume key is unknown for this disc - video can't be decrypted
Failed to open disc

What does it mean and how can I fix it?
Thanks in advance
Maik

[Woodstock]

When you copied it, you removed information that MakeMKV needs to decrypt the video. It should work fine from the original BD.