Midi interfaces duplicated in Cubase 7.5

Hi

I’m having this issue,my midi interfaces appears duplicated,e.g. “midi 8x8 1”…“2-midi 8x8 1”,and since I have assigned at midi device manager my synths I need to change the destination to the correct interface from time to time.
Is there a way to correct this?

Win 7 64

TIA