every time i import a dat file as a switch layer.

[hitmanimation]

Hello to all fellow animators and novices like me(mac).every time i import a switch dat file into my mouths layers the dat file isnt highlighted in the appropriate file it isnt highlighted so i cant use my dat file.Ive never had this problem with the pc version but mac is whole new ball game.can anyone help me please with this fundemental problem many thanks