[chirp_users] Chirp not communicating

Using Macbook Pro with OS 10.10.5 (Yosemite)Chirp 0.4.1Radio - Baofeng UV-5R I've been successful using older mac os' in communicating to this radio in the past I try to download the radio's program i get this error message  "An error had occurredcould not open port /dev/cu.vernebrownscomputer-Blu:[Ermo 16]resource busy : '/dev/cu.vernebrownscomputer-Blu' Not sure what I'm doing wrong or forgot to do.  did the cable check - it recognizes the type of chip in the cable as the debug instructions.