I should add to what John said to give the complete picture.

If you're using ASIO (with ASIO Always On checked), Using Ctrl+arrows in the notation window will actually use your DXi Synth if you have one enabled instead of your MIDI Output Driver. If you're using ASIO without ASIO Always On checked or MME, Band in a Box will use your MIDI Output Driver instead (when the song is not playing).

It will work with MME if your MIDI Output Driver is working, it's working fine with MME on my system.

Thanks,
Will

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