Apple MacBook Pro (17-inch, Late 2011) - Manual (Page 60)

60 Chapter 4 Problem, Meet Solution
You can install Mac OS X without erasing the disk, which saves your existing files
and settings, or you can erase the disk first, which erases all your data and leaves the
computer ready for you to reinstall Mac OS X and Apple applications.
After installing Mac OS X, you can go to the Mac App Store and re-download your
Apple applications.
Important: Apple recommends that you back up the data on the disk before restoring
software. Apple is not responsible for any lost data.
Restoring Your Computer to Its Factory Settings
When you restore your computer to its factory settings, everything on your computer
(your user accounts, network settings, and all of your files and folders) is deleted. Before
you restore, back up any files you want to keep by copying them to another disk.
Write down your network settings from Network preferences to make it easier to get
connected again after reinstalling Mac OS X.
1 Make sure you’re connected to the Internet by using an Ethernet or Wi-Fi network.
(To connect to a Wi-Fi network, follow the instructions on page 58.)
2 In the Mac OS X Utilities pane, select Disk Utility and click Continue.
3 Select the disk in the list on the left, and then click the Erase tab.
4 Select Mac OS Extended (Journaled) from the Format pop-up menu, type a name for
the disk, and then click Erase.
5 After the disk is erased, choose Disk Utility > Quit Disk Utility.
6 In the Mac OS X Utilities pane, select Reinstall Mac OS X and click Continue.
7 To reinstall Mac OS X and your applications, follow the instructions in the Mac OS X
Installer.