Message: "This mode requires a MIDI input device. Plug one in!"

[XS-Dez]

When I first loaded the program it played my MIDI files OK. Then after a few minutes it refused all my MIDI files with this message. I tried downloaded MIDI files, files created with Anvil Studio and files exported from Ableton Live. All stopped working with this message.

What is a "MIDI input device" and how do I plug one in?

[Keeper1st]

The MIDI input device would be your MIDI keyboard, generally. You must be selecting "Play Song" or one of the other "game" features where it scores how well you play the piece yourself, thus it is expecting a MIDI keyboard to be connected. If you want to avoid selecting the wrong mode in future and just have a MIDI playback only version, you can compile the viz branch instead of master.

[Partitionhlep]

if you're looking to just play midis without a midi input, use the practice song option when opening midis instead of play or learn song, because those modes require a midi input device, however the practice song option does not.