Apple says you shouldn’t reset the SMC without first trying other
troubleshooting tasks, such as force-quitting problematic apps and restarting
your Mac. However, Apple doesn’t mention any negative consequences of resetting
the SMC, 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 my Macs’ SMCs
many times with no apparent ill effects, and on occasion that did in fact turn
out to be the solution to a problem.
Before you can reset your SMC, you must shut down your Mac. 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.
Portable Macs with non-removable batteries: 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.
Portable Macs 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.
