The driver situation with Apple Bluetooth wireless keyboards and Windows 10 is horrible, even with the latest BootCamp drivers. Fortunately, a workaround is available, if you're patient.
Pair keyboard once
- Turn on the keyboard.
- Press and hold
Command + wuntil the keyboard light begins blinking, indicating the keyboard is ready to pair.
- Use Windows Bluetooth settings to pair the keyboard, entering the same code (e.g.
123456 Enter) on both internal and external keyboards.
Pairing the keyboard is very trial and error. 9/10 times, Windows will complain that the keyboard is not available for pairing. Just keep trying.
Finally, once the keyboard does pair, Windows will complain with a status
Uninstall Apple keyboard driver
Device Manager, such as from the Start menu.
- Identify the offending device, marked by a yellow warning triangle.
- Remove the device and uninstall the driver.
Pair keyboard again
Unpair and re-pair the keyboard, will probably take 20 more attempts.
Verify keyboard connectivity
Once the keyboard has paired, after uninstalling the keyboard driver, you can check whether the keyboard is finally fully connected, by pressing the Command (Start) button, etc.