When your Mac starts acting up – and they actually do, don’t believe the fanbois bullshit about perfect computing forever, there aint no such thing – you’ll probably run through some basic troubleshooting procedures, such as restarting, verifying permissions in Disk Utility, and using Safe Boot. I recommend that a well-rounded repair skillset should also include what’s known as zapping the NVRAM (formerly PRAM) and resetting the SMC. Personally, I use this procedure before Safe Boot & verifying permissions – it’s a general cure all for random Mac maladies.
Back in the day, the standard list of quick fixes for random Mac ailments (see, they’ve always existed!) included “zap the PRAM.” The P in PRAM stood for parameter (the RAM was just RAM—random access memory), and it referred to a small amount of special, battery-backed memory in every Mac that stored information the computer needed before it loaded the operating system. If the values in this memory got messed up somehow, you’d have start up issues, or maybe a number of strange behaviors when booted. So you could press a key sequence at startup to reset (or “zap” – which is far more emotive than “reset”, you reset a PC while you zap a Mac.) the PRAM, returning it to fresh factory values.
Back To The Future
Intel-powered Macs no longer use PRAM; they instead use something called NVRAM (NV for non-volatile). NVRAM, for all intents and purposes, serves the same role as PRAM (only fewer chunks of information are held). NVRAM is more reliable than PRAM so corruption is fairly uncommon, but if your Mac isn’t doing things as smartly as it once did or has an odd problem with video or sound particularly, then give it a zap. You won’t lose anything and it’s quick & easy to do. (Apart from the requirement for 6 fingers on each hand.)
Reset NVRAM by shutting down your Mac, then press the power button. As soon as you hear the startup chime, hold down Command-Option-P-R together – that’s 4 keys held down. Keep holding down those keys until you hear a second startup chime. Then let go and allow your Mac to continue starting normally. Then check the Startup Disk, Display, and Date & Time panes of System Preferences to make sure they’re set the way you want them.
iMac & Mac Pro only
If you’ve got a desktop Mac & after this procedure see nothing but a gray screen that doesn’t change for several minutes—no Apple logo, no progress bar, no second startup chime—don’t panic. Well, alright then, panic but only for a short time, 2-3 mins then read the rest of this post.
The most likely cause is that your Mac isn’t registering the key presses due to wonkiness with a USB device. Disconnect all USB devices (except your keyboard, if it’s a wired keyboard, else why hold the keys down? Duuuh), then repeat the process. If that doesn’t work and you’re using a wireless Bluetooth keyboard, try plugging in a USB keyboard instead. Once you’ve reset the NVRAM successfully with the wired keyboard, you can go back to your Bluetooth keyboard.
Reset the SMC
Now there is another component that holds system settings that sometimes needs clearing, of course there is. I mean why would you make it simple? Why should users be able to fix Apple fuck-ups too quick & easily? Anyway, I digress. (Megabyte is somewhat prone to digression)
SMC is the System Management Controller, which deals with power management, temperature monitoring and fan control, status lights, keyboard backlights, and a few other bits & pieces. If the SMC becomes confused, you’ll experience problems such as excessive fan noise, slow performance, apps that take forever to launch, batteries that don’t charge or charge very slowly, sleep and/or wake malfunctioning and more. Like zapping the NVRAM, resetting the SMC often resolves these PIA problems.
While Apple says to reset the SMC as a solution of last resort, they don’t mention any negative consequences, nor any way to determine for sure if the SMC is glitchy without resetting it and noticing that the problem went away. I’ve reset Mac SMCs lots of times with no side effects, often this has been the solution to a random problem.
Before you can reset your SMC, you must shut down your Mac, as per NVRAM procedure. After that, the procedure varies depending on the type of Mac you have.
Desktop Macs: Disconnect the power cord (either from the Mac or from the AC outlet). Wait 15 seconds and plug it back in. Then wait another 5 seconds and turn the Mac back on.
Mac laptops with non-removable batteries: (Retina MacBook Pro, MacBook Air) Make sure the Mac is plugged in to AC power. On the built-in keyboard, press and hold the Shift, Option, and Control keys on the left side and press the power button. Release all the keys at once, and then turn the Mac on normally.
Mac laptops with removable batteries: Disconnect the AC power cord and remove the battery. Press the power button, hold it for 5 seconds, and then let go. Put the battery back in, reconnect the power cord, and turn the Mac on normally.
Now, while I can’t guarantee a cure via these two methods, both of them can & do solve a variety of odd problems, and are definitely worth a few minutes of your time before calling in your local Mac fixit guy.
This procedure has an iOS equivalent, it’s quick & easy to do & you’ll be surprised how effective it is. I’ve used this method to rejuvenate problems from iPhone with sticky home buttons to an iPad with no picture showing. This method will also cure PIA problems like Apple ID passwords that wont stick or fingerprint IDs that disappear, weak WiFi reception & more. It’s both device and OS version agnostic, an across-the-board solution for various common problems.
You ready? Press & hold both your power button & home button together until the iDevice flashes off & restarts. That’s it, all done. Problem solved? Tell me about it in the Comments section below.