Apple MacBook Pro (13-inch, Late 2011) - Manual (Page 54)

54 Chapter 4 Problem, Meet Solution
If an audio device plugged into the audio port isn’t working
Unplug the audio device. Choose Apple () > System Preferences, and open Sound
preferences. In the Input pane, specify whether you want the port to be used for
Sound Input or Sound Output. Plug the audio device back in.
Note: If you’re running Windows on your MacBook Pro, the port supports only
audio output.
If you press the battery button, and all battery indicator lights flash five times quickly
Your battery needs to be replaced. Contact an Apple Retail Store or an Apple
Authorized Service Provider.
If you press the battery button, and the battery indicator lights flash from left to
right and then from right to left, five times in a row
Your battery is not recognized. Contact an Apple Retail Store or an Apple Authorized
Service Provider.
Repairing, Restoring, or Reinstalling Mac OS X Software
If you have a problem with your Mac software or hardware, Mac OS X provides repair
and restore utilities that may eliminate problems and can even restore your software
to its original factory settings. You can access these utilities from the Mac OS X Utilities
application, even if your computer isn’t starting up correctly.