Calibrating your Mac battery may resolve issues with the computer incorrectly detecting the status of the battery.
- Connect the charger to your Mac until it is fully charged.
- Once fully charged, leave it plugged in for 2 hours.
- Disconnect the charger and leave the computer running to drain the battery.
- When the battery is low enough, the computer will go into sleep mode. Either leave it sleeping for at least 5 hours or wake it up and Shutdown.
- Connect the charger again until it is fully charged.