The SMC (System Management Controller) is responsible for managing: power, battery, thermal, indicators, sensors, back-lighting, etc... (see below for a more complete list). If these settings get corrupted then your computer could behave erratically with the symptoms being associated with the setting listed above. It is usually suggested that you perform other simple diagnostic tests before resorting to resetting this – see my tutorial Apple-Q HowTo-Clean Your Mac: Solve Unwanted Mac Behaviour. I strongly suggest that you look through the above tutorial before you try resetting the SMC.If you still wish to go ahead then here is how...
