I used to use my WIN10 machine as NAS. Now I take out one of my harddrives out from it and connected to RT-AC68U USB2 port. Router detected the harddrive but just cannot show the content. The harddrive is 3.0 TB and formatted as GPT NTFS.
OP pulled the drive from his PC, and dropped it in an enclosure - wondering if this is a file permissions issue with ownership - if one telnet/ssh's into the shell, and does a list directory - what is seen there?