I receive Midi-Notes from USB-Midi Keyboard or from Cubase (sequenzer-software) with LoopBe(virtual Midi Port).

Problem: If i Play a Note, everything is fine. But when i finished to push a Key, Max gets the Note information a secondtime...

Whats wrong? How can i filter these note-off Information?

Problem: If i Play a Note, everything is fine. But when i finished to push a Key, Max gets the Note information a secondtime... 

playing-max-via-usb-midikeyboard

I think these will help you with this question, and probably the next one you are likely to ask.

https://cycling74.com/docs/max5/tutorials/max-tut/midichapter02.html

https://cycling74.com/docs/max5/tutorials/max-tut/midichapter03.html

Playing MAX via USB-Midikeyboard