How to Reset the System Management Controller (SMC) on a Mac

Method 1 of 4:

On MacBooks with a Non-Removable Battery

Click

. It's the apple icon in the upper-left corner in the menu bar. This opens the Apple drop-down menu.
Click Shut Down. It's in the Apple menu in the menu bar at the top.
Press and hold ⇧ Shift+Control+⌥ Option + Power Button. Press the buttons on the left side of the keyboard along with the power button.
1. The Touch ID button is also the power button if you have a newer MacBook Pro.
Release the buttons after 15 seconds.
Press the power button. Your MacBook will reboot as normal.

Method 2 of 4:

On MacBooks with a Removable Battery

Click

. It's the apple icon in the upper-left corner in the menu bar. This opens the Apple drop-down menu.
Click Shut Down. It's in the Apple menu in the menu bar at the top.
Remove the battery. Locate the latches on each side of the battery and slide them up. Lift the battery out. Make sure your Notebook is completely shut down before removing the battery.
Press and hold the power button for 5 seconds. Release the power button.
Reinstall the battery. Place the battery back in the battery compartment.
Press the power button. Reboot your Mac notebook as normal.

Method 3 of 4:

On iMac

Click

. It's the apple icon in the upper-left corner in the menu bar. This opens the Apple drop-down menu.
Click Shut Down. It's in the Apple menu in the menu bar at the top.
Unplug the power cord. Unplug the power cord from the wall, or the back of the monitor.
Wait 15 seconds. Allow your computer to sit for a moment.
Press and hold the power button for 5 seconds.
Plug the computer back in. Reattach the power cord to the back of the monitor and plug it into a power outlet.
Press the power button. Reboot your iMac as you normally would. The power button is located on the lower-left side of the back of the monitor.

Method 4 of 4:

On iMac Pro

Click

. It's the apple icon in the upper-left corner in the menu bar. This opens the Apple drop-down menu.
Click Shut Down. It's in the Apple menu in the menu bar at the top.
Press and hold the power button for 8 seconds.
Release the power button and wait 5 seconds.
Press the power button. Reboot your iMac as you normally would. The power button is located on the lower-left side of the back of the monitor.

power menu button apple

Jessica Tanner

Update 05 March 2020

You should read it