SMC Reset Older Laptops with Nonremovable Batteries
These models are included... All MacBook Air models. MacBook and MacBook Pro models after mid-2009, except the 13-inch mid-2009 MacBook.
Shut down the Mac. Press and hold these keys: left shift, left control, left option keys. While pressing these, also press the power button for 10 seconds. Release all the keys. Press the power button to start.
Note 1: This only works using the internal keybiard. Note 2: Don't use for Macs with the Apple T2 security from 2018.
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