Mac wireless keyboard

The following will require any USB keyboard and mouse. If you don’t have them, borrow or buy them, they are inexpensive!

1.     Connect the USB keyboard and mouse to the computer.

2.     Open System Preferences – Bluetooth

3.     Un-pair the wireless keyboard and mouse.

4.     Turn off Bluetooth

5.     Restart the computer in Safe Mode per the directions in https://support.apple.com/en-us/HT201262

6.     Restart the computer normally.

7.     Open System Preferences – Bluetooth

8.     Turn on Bluetooth

9.     Re-Pair the wireless keyboard and mouse.

10.  Unplug the USB keyboard and mouse and begin testing the wireless devices again. 

Assuming your keyboard is an Apple wireless keyboard, plug a lightning cable into your keyboard, and into your iMac. Do the keys work?

If the keys start working, you can unplug the cable and move on. Using a cable turns it into a standard wired keyboard and also re-pairs the keyboard.

Even after that, consider turning your keyboard's power off, then back on as well.