@Tony Thanks for your answer. I am giving up on this. I've tried a number of devices my different manufacturers and none work with this Mac. I don't feel like doing the work of setting up a dual boot...

I have an older Mac mini I wanted to turn into a wireless sniffer with Wireshark, to decrypt WPA for some troubleshooting. This is not to hack anyone--it's to determine who is grabbing all of the...