Inqscribe can locate a media file on different volumes only if the complete path name (the bit after the volume name) is exactly the same. So if the Windows path is C:\foo\bar\movie.mpg, then the complete path name is \foo\bar\movie.mpg.

That will match something like X:\foo\bar\movie.mpg, but won't match something like X:\Shared\foo\bar\movie.mpg.

On a Mac, that will match /Volumes/MyDisk/foo/bar/movie.mpg.

We're actually planning to deprecate the current path-matching. The future solution will let the user define "media library" folders, and those folders will always get searched for media files.