How to check your Mac’s hardware, interpret the results, deal with problems, and tackle tricky intermittent faults.
hardware test
What should you do when you try to restart in Diagnostics Mode and can’t? And how to check and restore a Recovery partition.
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.
