Help with USB drive

I have installed ATV V. 4.0.6… I ran the installer for nitoTV. I can not see my external USB 2tb drive. I formatted drive with my mac and copied over my folders with my movies in it. I then ran installer, rebooted machine and plugged in HD after main menu came up. When I go to nitoTV click on files I see nothing but if I go to maintenance, settings itunes storage and try to change machine to see external it sees the drive and wants to reformat it. Why is it not seeing it the other way cause I do not wanna reformat the drive and copy video back to drive. Thanks for all your help.