It seems like your Mac won't turn on for a black screen issue. What you need to do first is to try adjusting the brightness of your display by pressing F1 or F2. Your Mac makes the startup sound and the keyboard lights begin to glow but you still don't see the Apple logo, that may be because the brightness of your display has been turned down to the lowest by mistake.
Black screen maybe caused by software or firmware issues, hardware damage, power issues, poor contact, etc. If your Mac is still not turning on after you adjust the brightness, try the following methods to fix the black screen on your Mac.
- Check the power supply
- Perform a Power Cycling
- Disconnect the peripherals
- Wake up your MacBook from sleep mode
- Reset SMC
- Reset NVRAM settings
- Boot into Safe Mode
- Repair the startup disk
- Reinstall macOS
To prevent data lose, you need to back up your data after you turn on your Mac. If you don't have any backup and have lost data because this issue, you can use iBoysoft Data Recovery for Mac to ask for help. More details are included in recover files from MacBook that won't turn on.