An update froze my MacBook Pro
Q My MacBook Pro froze when installing the High Sierra 10.13.4 update. Now it won’t start up properly, and just sits there with a dark display. What can I do?
A That update included an EFI (Extensible Firmware Interface) update for every Mac, which for some people has brought trouble and left their Macs in limbo.
Force your MacBook Pro to shut down by holding the power button, leave it for a few seconds, then power on and immediately hold ç+R to enter macOS Recovery. If the EFI update went wrong, recent models should automatically recover, displaying a progress bar while they do. Macs that still play a startup sound will inform you by making three long, three short, and three long tones. However, recent models of MacBook Pro are silent at startup.
Once in Recovery, open Disk Utility and run its First Aid feature on your startup disk. Afterwards, you should use Recovery’s option to reinstall macOS over the top of your existing installation. If you can’t get into Recovery, try resetting the SMC by following Apple’s steps for your model at bit.ly/mfrstsmc.
If your Mac continues to have problems, it’s worth running hardware diagnostics by following the advice given at bit.ly/mfappldiag or bit.ly/mfapplaht (depending on the age of your Mac). If all else fails, make an appointment at your nearest Genius Bar.