If your Apple computer is acting strangely, such as random restarts, muted audio, ports not reading/receiving information, etc., you can try to reset certain systems settings via a hardware-related reset. Here is some general information on the whys, whens, and hows, of resetting your Apple computer.
***BEFORE YOU RESET NVRAM, PRAM, or SMC: Disconnect all drives, speakers, external displays and keyboards to make sure nothing interferes with the resetting process.***
What the SMC doesThe SMC is responsible for these and other low-level functions on Intel-based Mac computers:
How to know if you need to reset the SMCThese symptoms might mean that an SMC reset is necessary:
How to reset the System Management Controller (SMC) on your MacBefore you reset the SMCTry each of these steps in this order before you reset the SMC. Test the issue after each step to see if the issue still occurs.
If you're using a Mac notebook that's having power or battery issues, follow these steps:
If the issue still isn't resolved, you might need to reset the SMC using the steps below. * On some keyboards, the Option key is also labeled Alt. How to reset the SMC on Mac notebooksIf you have a MacBook Pro (2018), skip ahead to the section that deals with your Mac. To reset the SMC on a Mac notebook, first determine whether the battery is removable. Most older Mac notebooks have removable batteries. Mac notebooks that have nonremovable batteries include MacBook Pro (Early 2009 and later), all models of MacBook Air, MacBook (Late 2009), and MacBook (Retina, 12-inch, Early 2015 and later). Learn more about Mac notebook batteries. If the battery is nonremovable:
If the battery is removable:
How to reset the SMC on Mac desktop computersIf you have an iMac Pro, skip ahead to the section that deals with your Mac. Follow these steps for iMac, Mac mini, Mac Pro, and Xserve.
For Intel-based Xserve computers that aren't responding, you can shut down locally or by using remote commands. You can also press and hold the power button for 5 seconds. How to reset the SMC on a Mac that has the Apple T2 Security ChipFollow these instructions for Mac computers that have the Apple T2 Security Chip. Mac desktop computers with the T2 chipTry this first:
If that doesn't resolve the issue, follow these steps:
Mac notebook computers with the T2 chipTry this first:
If that doesn't resolve the issue, follow these steps:
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What the NVRAM/PRAM does
Reset NVRAM or PRAM on your MacIf your Mac has issues related to settings stored in NVRAM or PRAM, resetting it might help. NVRAM (nonvolatile random-access memory) is a small amount of memory that your Mac uses to store certain settings and access them quickly. PRAM (Parameter RAM) stores similar information, and the steps for resetting NVRAM and PRAM are the same.
Settings that can be stored in NVRAM include sound volume, display resolution, startup-disk selection, time zone, and recent kernel panic information. The settings stored in NVRAM depend on your Mac and the devices that you're using with your Mac. If you experience issues related to these settings or others, resetting NVRAM might help. For example, if your Mac starts up from a disk other than the one selected in Startup Disk preferences, or a question mark icon briefly appears before your Mac starts up, you might need to reset NVRAM. How to reset NVRAMShut down your Mac, then turn it on and immediately press and hold these four keys together: Option, Command, P, and R. You can release the keys after about 20 seconds, during which your Mac might appear to restart.
If your Mac is using a firmware password, this key combination does nothing or causes your Mac to start up from macOS Recovery. To reset NVRAM, first turn off the firmware password. When your Mac finishes starting up, you might want to open System Preferences and adjust any settings that were reset, such as sound volume, display resolution, startup disk selection, or time zone. |
Learn more
- If you're using a desktop Mac instead of a notebook, and settings such as sound volume or time zone are reset every time you shut down and unplug your Mac, you might need to replace the battery inside your Mac. This small battery is on your computer's logic board, and it helps NVRAM retain settings when your Mac is unplugged. You can take your Mac to an Apple service provider to replace the battery.
- If you experience issues with sleep, wake, power, charging your Mac notebook battery, or other power-related symptoms, you might need to reset the SMC (System Management Controller).
- Resetting the SMC doesn't reset or otherwise change the contents of NVRAM or PRAM on Intel-based Mac models.