Hi Lukalfb,
It sounds like you've taken some great troubleshooting steps already. This may be unexpected, but there is a certain circumstance where it would be considered expected behavior, so you would not be able to resolve it by troubleshooting. Do you have FireVault enabled? If so, that would explain what is happening.
If not, let's explore further and see what we can find to resolve the issue for you.
If you use Boot Camp on your MacBook Pro, try adjusting the below settings.
"Manually adjust keyboard backlighting
In Windows on your Mac, do any of the following:
- Adjust keyboard backlighting: Press the increase keyboard brightness key or the decrease keyboard brightness key.
- Turn keyboard backlighting off: Press the decrease keyboard brightness key until the keyboard is no longer lighted.
- Turn keyboard backlighting on: Press the increase keyboard brightness key until the keyboard is bright enough for your needs.
- Use function keys to adjust keyboard backlighting: Press the F5 key to decrease keyboard backlighting, or press the F6 key to increase keyboard backlighting. You may need to press and hold the Fn key as you press the F5 or F6 key.
If the keys don’t adjust the backlighting, make sure you have the latest Windows support software installed. See the Apple Support article Download and install Windows support software on your Mac."
Reference: Set keyboard brightness in Windows with Boot Camp on Mac
If neither of those things apply we recommend you try to "Start up your Mac in safe mode", to see if the same thing happens. Starting in safe mode can help you identify whether issues you’re experiencing are caused by software that loads as your Mac starts up.
We hope that helps you find a solution. We're always happy to help if you need us.
Cheers!
