Are there any other issues you are having with your mac book before you try the following
Try and reset the System Management Controller (SMC)
If the battery is nonremovable:
-
Choose Apple menu > Shut Down.
-
-
After your Mac shuts down, press Shift-Control-Option on the left side of the built-in keyboard, then press the power button at the same time. Hold these keys and the power button for 10 seconds.
-
-
Release all keys.
-
-
Press the power button again to turn on your Mac.
-
+
* Choose Apple menu > Shut Down.
+
* After your Mac shuts down, press Shift-Control-Option on the left side of the built-in keyboard, then press the power button at the same time. Hold these keys and the power button for 10 seconds.
+
* Release all keys.
+
* Press the power button again to turn on your Mac.
If has removable battery:
-
Shut down your Mac.
-
-
Remove the battery.
-
-
Press and hold the power button for 5 seconds.
-
-
Reinstall the battery.
-
-
Press the power button again to turn on your Mac.
+
* Shut down your Mac.
+
* Remove the battery.
+
* Press and hold the power button for 5 seconds.
+
* Reinstall the battery.
+
* Press the power button again to turn on your Mac.
Are there any other issues you are having with your mac book before you try the following
Try and reset the System Management Controller (SMC)
If the battery is nonremovable:
Choose Apple menu > Shut Down.
After your Mac shuts down, press Shift-Control-Option on the left side of the built-in keyboard, then press the power button at the same time. Hold these keys and the power button for 10 seconds.
Release all keys.
Press the power button again to turn on your Mac.
If has removable battery:
Shut down your Mac.
Remove the battery.
Press and hold the power button for 5 seconds.
Reinstall the battery.
Press the power button again to turn on your Mac.