the volume key is unknown for this disc *HELP*

[britney98]

So i tried to download a mkv of a blu ray i own an when i put the disc in it said
MakeMKV v1.10.6 darwin(x86-release) started
The program can't find any usable optical drives.

so i tried draging the bdmv into the source button and that didnt work and it said
the volume key is unknown for this disc - video can't be decrypted

anyone know how I can fix this?

[Woodstock]

MakeMKV depends upon the information in the directory of the BD to calculate the volume key. Did you receive any error messages as the disk loaded?