At times, Macs can behave abnormally for no reason: the lights don’t work properly, the volume Settings mess up, the display resolution changes, or it doesn’t boot at all.
Some problems can be resolved by restarting the computer. However, sometimes it is necessary to reset SMC, PAM, or NVRAM.
What is SMC in a Mac?
The System Management Controller, or SMC, is a chip found in Intel-based Macs. It involves many of the physical parts that run the machine, including LED lights, keyboards and other peripherals, cooling fans, and power buttons. It also plays a role in the behavior of hard drives, the behavior of Macs in sleep mode, and the power supply.
When should the SMC be reset?
The SMC is responsible for many of the functions in the Mac, so it’s worth reconfiguring whenever you find your computer’s hardware working in unexpected ways. The following are the main symptoms of a recommended reset of SMC:
Abnormal battery or status light performance
The keyboard backlight doesn’t work properly
The MacBook cannot boot up when opened
The power adapter indicator does not reflect what it is doing
Fans operate at unusually high speeds, especially under low loads
The trackpad does not work
Your computer cannot connect to Wi-Fi
The target display mode was unexpectedly opened or closed
Application ICONS bounce for a long time when opened
Even at low CPU loads, your computer is slow
The computer shuts down slowly.
When the Mac fails to boot
How do I reset SMC on a Mac
There are several different ways to reset the SMC, depending on the Mac type.
Reset the SMC on the M1 Mac
No longer need to reset SMC on a MacBook or Mac Mini powered by Apple Silicon. Actually, you can’t, because Apple’s chip doesn’t have a system management controller.
If you encounter any problems that would normally be resolved by resetting the SMC, some users recommend turning off the Mac for 30 seconds before restarting the computer to resolve the problem.
Reset SMC on Intel MacBook
To reset the SMC (model 2018 or later) on a MacBook with an Apple T2 security chip:
Close the Mac.
Press and hold the power button for 10 seconds, then reboot.
If you can fix the problem, turn off the Mac again.
Hold down the right Shift key on the left Option key while holding the left Control key for 7 seconds.
Keep these keys pressed down while pressing and holding down the power button for 7 seconds.
Release all buttons and wait for a few seconds. Now restart your MacBook.
To reset the SMC on a MacBook with a non-removable battery (mainly before 2018) :
Close the Mac.
Hold down the Shift key, control and options on the left keyboard. Now hold down the power button (or Touch ID button).
Hold all keys for 10 seconds.
Release all keys and open the MacBook.
To reset the SMC on older MacBooks with removable batteries (mainly pre-2015) :
Close the Mac.
Remove the battery.
Hold down the power button for 5 seconds.
Reconnect the battery and turn on the MacBook.
Reset the SMC on an iMac, Mac Mini, or Mac Pro
To reset the SMC on a desktop Mac with a T2 chip (such as the iMac Pro) :
Close the Mac.
Hold down the power button for 10 seconds.
Release the power button, wait a few seconds, and then restart the computer.
If the problem does not go away, turn off the Mac again.
Unplug the power cord.
Wait 15 seconds.
Reconnect the power cord and wait five seconds.
Turn on your Mac.
What are PAM and NVRAM in a Mac?
The PAM (parametric random access memory) and NVRAM (non-volatile random access memory) hold information about the MAC configuration.
This includes things like date and time, as well as desktop, volume, mouse, and other control Settings. These memory areas are powered by small batteries, so these Settings are not lost each time the computer is turned off.
When should you reset the PAM or NVRAM?
Problems with PAM or NVRAM are usually software related. Due to memory problems, the computer may forget certain Settings or may experience connection problems. Try resetting when you experience any of the following symptoms:
Volume does not respond correctly
The boot volume is not set (you will see a question mark before the computer starts)
Strange mouse scrolling and clicking speed
The keyboard is not responding properly
Time zone or clock error
Display resolution changes or does not change
The airport problem
The computer shuts down slowly.
How do I reset the PAM or NVRAM on a Mac
If you have an M1 Mac, there is no need to reset NVRAM. (This process will occur automatically when the computer is restarted.)
For older Macs, you don’t need to know if your Mac is NVRAM or PAM, because the process for resetting both is the same:
Close the Mac.
Press the power button.
Press the CMD, Option, P, and R keys simultaneously before the gray screen appears.
Press and hold these keys until your computer reboots and you hear the boot sound again.
On a Mac with a T2 security chip, hold down the button until the Apple logo appears and disappears a second time.
Release the button.
After the reset, certain Settings, such as time, volume, mouse Settings, and keyboard preferences, may be lost.