Accessory not supported message

I was getting frequent ‘This accessory is not supported by this device’ pop-ups on my 10.5” iPad Pro (128G/WiFi/Cellular). I was scratching my head because I didn’t think I had any accessories connected and I had Bluetooth disabled.

But I did have an accessory connected, just not through the lightning port. It was the Smart Keyboard, which gets both its power and data connections from the little magnetic 3-dot connector on the long edge of the iPad. I tried typing on the Smart Keyboard (which I don’t do that often), and it worked intermittently. Sometimes not recognized at all, sometimes typed OK for a little while then quit, sometimes put up the wrong letter, etc. So I removed the Smart Keyboard. No more “not supported” message. I then got a new Smart Keyboard and attached it. iPad is now OK: no typing problems, no “not supported messages”, no problems of any kind.

If you’re getting mysterious “Accessory not supported” messages and you have a Smart Keyboard, that might be the problem.