How to Restore a MacBook
There are lots of reasons to restore a laptop. The sale of a system, a fresh start, or the recovery from a Hard Drive issue, to name a few.
Macs running OS X Lion and newer versions of OS X include a recovery mode boot-up option. You can boot into the recovery environment, also known as “Lion Recovery,” by using a special key combination while your Mac is booting up. You can restore your MacBook Air to its factory default state using this mode; the MacBook Air downloads the required data from Apple and reinstalls Mac OS X on your computer. You can also restore your Mac from a Time Machine backup.
Step 1: Enter recovery Mode
Press the “Command” and “R” keys on your keyboard at the same time and hold them down until the Apple logo appears. A “Mac OS X Utilities” window appears after the Apple logo. If you don’t see the window, try restarting your MacBook Air and pressing the “Command” and “R” keys earlier in the boot process.
Step 2: Wifi
Connect to a wireless network by clicking the “Wi-Fi” icon at the top-right corner of your screen, selecting your wireless network and providing its password.
Step 3: Install
Click “Reinstall Mac OS X” in the Mac OS X Utilities window and click “Continue.”
Step 4: Choose your drive
Select your Mac’s internal hard drive by clicking it in the list that appears and click “Install.”
Step 6: Authenticate
Type your Apple ID and password for the Mac App Store into the boxes to confirm your eligibility. Your Mac downloads about 4 gigabytes of data from the Internet and restores Mac OS X to its original state.
If you do not see your Drive
If your Mac's hard drive isn't visible during the installation process, you will need to format the hard drive. (WARNING: THIS WILL ERASE THE DRVE)
Step 1: Disk utility
If the Installer is running, quit it and exit to the OSX Utilities Screen. Click Disk Utilities.
Step 2: Format Drive
Select your drive from the column on the left. Next select the Partition dutton on the right. Under Volume Scheme, choose One Partition, the hit the apply button in the bottom right.
Step 3: Continue the restore
When the partitioning is complete, quit disk utility, and continue your OS restore.
Internet recover w/out Recovery Partition
If your hard drive has had a serious issue, been improperly formatted, or is brand new, you might not have a recovery partition.
Step 1: Boot
Boot the system holding down command + R
Step 2: Wifi
When the system boots, the middle of the screen will have a dropdown that will allow you to connect to the internet wirelessly. Do so.
Step 3: Restore
Follow the prompts and the system will download and configure the recovery environment.