I had the same problem (Midi File Type 1 with all channels in one track), and based on the discussion I did something I thought would be too simple, but it worked ...
I "Saved As" the file as Midi Type 0 and closed it. Then I Open-File the Type 0 file and it was opened with each channel on its own track.
Repeating myself, simple but it worked.
This works with Sonar X and later, but only dependably when the midi file has only one track and multiple channels. (You may delete empty tracks if needed.)
How to import MIDI separating by channel
in Cakewalk by BandLab
Posted
This works with Sonar X and later, but only dependably when the midi file has only one track and multiple channels. (You may delete empty tracks if needed.)