Can't import audio into instrument tracks so the menu option is disabled.
What type of audio file are you attempting to import? Could the filename extension be mis-asigned?
What process are you using to import? Drag-drop from explorer into Track view? Or, select audio track and File > Import > Audio ?
I can't to do even File > Import > Audio btw. These type of file are WAV.
Easy way is open the browser and drag and drop the file to an empty space in the track pane. This will create an audio track.
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