This is how to reset SMC on most modern Mac laptops, none of which have a removable battery:
- Shutdown your MacBook Air / MacBook Pro
- Connect the power adapter to the Mac
- On the MacBook / Pro’s keyboard, hold down the Shift+Control+Option keys and the Power button at the same time
- Release all keys and the power button at the same time – the little light on the MagSafe adapter may change colors briefly to indicate the SMC has reset
- Boot your Mac as usual