Any Solution to This Random MIDI Notes Behavior

Having upgraded to C6 (Cubase 6.0.5) from C5, I heard random notes (say C2) subsequently after playing/pressing, say G5 on my keyboard. I checked this behavior (random notes) by switching to my other softwares (Nexus 2, Kontakt 4, and others), and it still happened . I am on PC Windows 7 64 bit. Am I missing something in my setup? This did not happen under C5. Please advise. Thanks.

Have you selected the specific MIDI port for your device for the input and not All, or set All to only be associated with your device?

I had this and it turned out to be a faulty USB 3.0 port. Check the free MIDIOX program and see if the random notes are being seen there (outside of Cubase).

Thanks for the input. My audiocard is Fireface 800, and attached is what I have under Cubase 6 Device Setup:

I hope that the setup is OK.
Under Device Setup.pdf (96.4 KB)