It used to be that you could drag and drop and MIDI file onto a blank project and it would import the file and create however many MIDI tracks was necessary. With 2017.01 it won't allow the file to be dragged and dropped. You have to "File - Import - MIDI" to import the file. Not too bad but I wonder why they would remove this useful functionality?
In other words was this done deliberately or is it a bug in 2017.01?
 
Thanks
ZT

Run Sonar as administrator.

I believe you mean "do not run SONAR as administrator."
 
Windows prevents drag and drop from the OS into SONAR when the application is running as administrator.
 
Of course, drag and drop will work from the media browser whether SONAR is running as administrator or not.

Thanks scook, that was the answer.