The Magic & Mystery Behind SMC and NVRAM / PRAM Resets
Are you having problems with your MacBook, Mac mini or iMac? Have you tried SMC and PRAM resets? If not, it’s worth trying. These magic resets can often fix simple software and hardware issues. They certainly can’t hurt and they just might help.
SMC reset? Sounds technical.
SMC, or System Management Controller, is a low-level function that does more or less what it says, it manages system controllers. Straight forward enough for you?
It regulates various hardware functions, mostly those related to power and power consumption. Problems with a fan spinning too high, LED indicators not working, sleep/wake issues, sensors not reading and a whole host of other problems, can all be solved with an SMC reset. It handles a lot, but here’s a 99% complete list of problems you might run into that could be solved with an SMC reset:
- MacBook does not respond to the opening and closing of the display.
- MacBook does not respond to pressing the power button.
- MacBook is not charging the battery properly.
- MacBook is not regulating the temperature properly through use of the fans.
- MacBook does not Sudden Motion Sensor (SMS)
- MacBook does not adjust screen or keyboard brightness in response to ambient light.
- Manually adjusting keyboard backlight brightness is non-functional.
- MacBook’s white LED “status indicator light” does not behave properly.
- MacBook’s battery status indicator lights are not responsive or otherwise do not behave properly.
- Problems with an iMac using selecting an external display for video-out.
How does the SMC differ from NVRAM/PRAM?
We’ve talked a little bit about PRAM resets here before. Since then I have found some new info and wanted to clear some things up, so included in this post is a full discussion of NVRAM/PRAM.
NVRAM (Nonvolatile Random Access Memory) and PRAM (Parameter Random Access Memory) perform the same function. NVRAM is the newer version but for all intents and purposes, they do the same thing. NVRAM is basically RAM that doesn’t lose its data when you turn it off. They store information for programs and apps that run when the OS starts. These can be things like volume and display settings, wi-fi and Bluetooth connections, timezone, and startup disk choices. Apple doesn’t release all of the information on what is stored here, but I found an archived version of their website with a fairly full list. Here is what they included in 2012:
- Status of AppleTalk
- Serial Port Configuration and Port definition
- Alarm clock setting
- Application font
- Serial printer location
- Autokey rate
- Autokey delay
- Speaker volume
- Attention (beep) sound
- Double-click time
- Caret blink time (insertion point rate)
- Mouse scaling (mouse speed)
- Startup disk
- Menu blink count
- Monitor depth
- 32-bit addressing
- Virtual memory
- RAM disk
- Disk cache
The real question is “why not?” There are very few side effects, if any, of trying these resets. At worst you may lose a few custom boot settings. There’s no point in doing them if you’re not experiencing any issues, but it is the first thing I do everytime there is an issue. After doing these resets you know that your machine will be working the way Apple intended it to, assuming you don’t have a much larger issue. They won’t fix everything, but they just might fix your problem. So, why not try it?
How to perform this magic.
Gaze into my mysterious grimoire of Mac tricks and learn these relatively simple fixes.
The SMC Reset spell:
There are slightly different steps depending on what Mac you are trying to reset. I’ll start with the easiest one first.
If you are using a desktop Mac, like a Mac Mini or iMac, use the following steps;
- Shut down your computer.
- Unplug it and wait 15 seconds.
- Plug it back in, turn it on and Viola!
See how it easy it is.
On to the laptops. There are a couple more steps, but it’s still pretty easy.
- Shutdown, then unplug your MacBook’s MagSafe power adapter.
- If you have a removable battery unplug that, too.
- Press Left Shift+Control+Option+Power Button.
- Hold these buttons for 10 seconds.
- Plug your MacBook back in and start it up.
- Enjoy the fruits of your labor.
The NVRAM/PRAM incantation:
This will be the same for all Mac’s. Once again make sure your Mac is shut down.
The tricky part is going to be you need to turn it back on and hold down the Option+Command+R+P keys. The easiest way to do this is to hold down Option+Command+R with your left hand, press the power button with your right hand, then quickly bring it to the P key. On a MacBook you might be able to reach the P key and the power key at the same time with different fingers. It’s up to you. Just make sure you have all the buttons held before the Apple loading screen starts.
Now that you have figured out the best way to press all those key, just wait. You’ll hear your computer make the startup chime, keep holding those keys. After between 10 to 30 seconds, your Mac will restart. You can let go now and let it start normally. I like to run through the NVRAM/PRAM reset three times before letting it start normally. Some people do more, some people do less.
That’s all there is to it. You have successfully learned the mysterious secret of the SMC and NVRAM/PRAM reset. I recommend doing both if you are having an OS or hardware related problem, after all it really can’t hurt. Besides, if you’re going to start casting magic spells on your computer you might as well use your full strength. You’d be amazed at the number of quirks I have seen relieved by this simple method.
If you’re still experiencing problems, then you may have a larger issue and might need a more experienced repair technician to take a look.
Show Your Love For This Post
With macOS 10.13, otherwise known as High Sierra, Apple introduced an ambitious EFI update. Several of the changes include: the introduction of the Apple File System, support for NVMe drives, and the usual batch of security updates. However, these EFI updates can cause some unwanted behavior when you test your Apple computer’s memory. At Beetstech, we use a long-time industry standard, MemTest86 to perform a comprehensive test of each computer’s RAM.
But never the type to blindly accept test results, strange testing outcomes led us to discover a bug in MemTest86 affecting computers running the new EFI firmware. In short, the newly updated EFI causes MemTest86 to incorrectly fail certain tests. But there is good news: while normal operation of MemTest86 is limited under these new EFI updates, we also discovered some simple workarounds for testing your Apple’s memory in MemTest86.
So let’s dive into how we discovered the MemTest bug, devised a reliable work-around, and get into some nitty gritty details of MemTest86 operation.
They go by “jumper pads”, “short-circuit pads”, “power pads”, and “power-on pads”. Whatever you call them, there are two bits of metal on your MacBook logic board that can force your laptop to boot up, even if the power button won’t do the trick.
Anywhere premium products are produced, there are unsavory folks trying to make a quick buck selling cheap knockoffs. It happens in every industry, from clothes to food to tech. But in recent years, counterfeit electronics have surpassed nearly all other categories of counterfeit goods by dollar value, and Apple, being the de facto high-end electronics manufacturer, makes for a prime target.
But you’d never be caught buying counterfeit electronics, because you can tell the difference, can’t you?
Remember the good ol’ days of carrying a spare battery, upgrading your own RAM, maybe even adding a second hard drive? If you’re an Apple user, those luxuries may be behind us, but upgrading your own solid state drive is still a privilege the Apple overlords allow us to have, for now that is.
Despite retaining the ability to upgrade your own SSD, ever since Apple introduced their proprietary “blade” SSDs in 2010, the task hasn’t been as simple as it once was. Apple talks up read and write speeds, but they rarely dive into the nitty gritty details of the technology behind the SSDs they use — drives specially designed only for Apple computers.
After countless questions, both from customers and our own staff, we decided to start our own investigation into the hardware involved. You have to be a bit of a private eye to uncover the secrets behind these drives, and the deeper we looked, the more surprises we found.
Owners of a Unibody MacBook Pro laptop are probably already aware that failure of the hard drive flex cable is a common issue. While it affects just about the entire Unibody lineup, the Mid 2012 MacBook Pro 13″ (Model A1278) is especially prone to this type of failure.
What is it that makes the Mid 2012 release special in this regard? A design flaw in the flex cable that seems to be compounded by the properties of the aluminum housing.
Our repair services department noticed this issue when they’d replace a bad cable, only to have the customer return a few months later with another bad cable. And possibly again with yet another bad cable. It didn’t matter if we used a used cable or a new cable in the replacement. Customers kept returning with the same persistent issue. We had to figure out what was causing the issue and find a solution.