I set up a 5ghz network on my time machine (time capsule? the router with a hard drive in it). Just noticed this problem that is happening on a late 2011 Mac mini on 10.11.4. I have one router, two ssids (one called "name" and other called "name 5ghz" both have same password. I only connect my 2 macs and xbox to the 5ghz channel so that it is faster and easier to download files from the web and my time machine. The rest of my 10-15 devices stay on 2.4. I will boot up, it will connect to 2.4, I will click on 5ghz, it will connect, and then 10 or 15 minutes later it will go back to 2.4. Sometimes this will happen while I am downloading files which is pretty annoying. Is there a setting somewhere that prioritizes one ssid over another? I read somewhere on apple's site that the iphone automatically chooses the strongest access point, is that true with macs? If so, that really doesn't make sense to me. The mac never moves like an iphone would, so why would it choose the stronger band(when the faster band would be ideal)? I know the 5ghz is going to be weaker (2.4 is 98% signal strength, 5 is 80%) And the speeds (speedtest twice, averaged): 2.4 = 19.75 down, 4.12 up 5 = 52.86 down, 4.35 up So tldr: how can I make my mac stay on "name 5ghz" without forgetting the 2.4 ghz channel "name", which I still require when running some programs. Like I said, I just set up the 5ghz band a couple of weeks ago and know next to nothing about how mac interacts with my setup. I searched around and found similar problems but they were older threads so not sure how valid they are.