I am trying to use usb_cdc_msd composite demo from freescale usb stack 4.1. on k60n512vmd100 tower kit. My PC detects both storage and virtual com port. I'm able to access storage but when I try to open COM port it says "Port is being used by another application". I've windows 8.1 on my PC. I thought it was driver issue but when I ran cdc_demo from example projects then virtual com port is working properly. Can someone help ??