I am still quite new at all this so please be patient with me. I bought the “official” OSMC AC wifi dongle, it claims to be a simple plug and play dongle. Plug it in, boom my 5ghz network pops up, I try to connect, nothing happens. I previously bought a Edimax AC dongle and I had the same problem. Both dongles work fine with my Mac, so I’m ruling out that it’s my router? Is there something I’m missing within the Pi? I’m running the most current version of OSMC.
Have you disabled the internal wifi on the pi3?
Done by disabling the drivers by creating the file /etc/modprobe.d/wifi-blacklist.conf and adding:
blacklist brcmfmac
blacklist brcmutil
You may also find rm /lib/firmware/mt7610u_sta.dat helps resolve the issue for you. I’ll take care of this in a future update