What should you do when you try to restart in Diagnostics Mode and can’t? And how to check and restore a Recovery partition.
hardware test
What happens in your Mac when you press the Power button? Before it loads the EFI firmware, it goes through self-testing, and initialising key chips.
When should you reset your SMC and NVRAM, repair permissions, install a Combo update, or re-install the whole of macOS?
Shutdown cause codes, wake reasons, ACPI, and sleep states – diagnosing problems from hardware events.
How to run Apple’s diagnostic software to work out whether your Mac has a hardware fault – and how to interpret its error codes.
How much is the data stored on your Mac’s drives worth? DriveDx is a utility which could save you from that loss.
What to do when your Mac won’t start up, and is acting dead, or at least mortally wounded.
