Sometimes your Mac might not power on, or might be having weird issues. There are a couple of “magical” reset button combinations that are generally harmless and pretty easy to do. These techniques are most useful on the MacBooks. For example, the iMac doesn’t have a SMC reset key combination. Instead, you can just unplug the iMac from the power source and plug it back in.
If these resets don’t solve your problem, the issue is most likely not so easily resolved, but these are really useful tools to have at your disposal in the rare event that you should need them. As a service technician these are the first thing I do when I see a misbehaving machine, and I don’t even think about it anymore.
The descriptions below are a little detailed, but I’ll try and give you the necessary highlights without all the confusing details.
First, make sure the machine is powered off. The sleep light on the front right corner that blinks when you first turn the machine on and kind of slowly strobes when it’s sleeping should be off. If you have a MagSafe Adapter plugged in, you should see the color of the light change.
The SMC reset is a key combination of:
Shift + Control + Option + Power Button
After the SMC reset you can power on the machine as usual.
The NVRAM/PRAM reset is a key combination of:
Command + Option + P + R
This is done before the gray Apple logo appears on the screen, or shortly after the startup chime if you can’t see anything on the screen. You should hear the machine make the startup chime again, keep pressing those keys down until you’ve heard the chime at least three times and then release. After that the machine should start as usual.
Sometimes those key combinations can resolve the issue, sometimes they don’t do anything. If it doesn’t help, give us a call and we’ll help you decide how to proceed.
Links to the Apple Support articles below: