At some point, everyone will experience a hard drive failure.  When this happens, a Time Machine backup can save your data.  Here are instructions on how to restore all applications and personal files from a Time Machine backup onto a new hard drive. Time Machine is a backup application made by Apple. It comes bundled with every Mac that shipped with OS X 10.5 or higher. It can be used to backup the contents of your Mac’s internal hard drive to an external hard drive or to an Airport Time Capsule. I’ve written previously about the importance of backups and how to set up and monitor Time Machine. The restore process requires you to first install OS X onto the new hard drive and then restore everything from your most recent Time Machine backup.

(If you’re looking for instructions on how to restore an entire Time Machine backup on to a new Mac read this.)

These instructions assume that your Mac is using OS X 10.7.0 or higher and that you’re restoring to the same Mac that was used when you made the Time Machine backup.

OS X Lion (aka OS X 10.7) introduced a feature called OS X Recovery. OS X Recovery lets you reinstall OS X from either the Recovery Partition or over the Internet from servers that Apple operates. Since your Mac has a new hard drive installed it won’t have a Recovery Partition so you’ll need to reinstall OS X over the Internet.

Here’s how to use Internet Recovery.

• Turn on your Mac and hold down Command-R.
• Either plug-in an ethernet cable or you’ll be prompted to select your Wi-Fi network and then enter the password for your wireless network. (Note:  Your Wi-Fi network needs to use WPA or WPA2 encryption. WEP encrypted networks are not supported.)
• When your Mac eventually starts up, you’ll see a window named OS X Utilities.
• Choose the option to install OS X. This will install the version of OS X that originally came with your Mac. Wait for the installation to finish. The amount of time that is required varies based on the speed of your Internet connection. (Important Note: In order to restore everything from your Time Machine backup your Mac needs to using the same version of OS X that was installed on your Mac when you made the Time Machine backup.)
• After the OS X install finishes, create a user account that uses a different name then the name of your user account in your Time Machine backup.
• Go to your Applications folder and open the App Store. Login using your AppleID and then click on Purchases.
• Install the version of OS X that your Mac was using when you made your Time Machine backup.

Now that OS X has been installed on your new hard drive, it’s time to restore everything from Time Machine.

• Again, turn on your Mac and hold down Command-R. Your Mac will now startup from it’s Recovery Partition that was created on your Mac’s new hard drive.
• You’ll see a window named OS X Utilities.
• Choose the Restore From Time Machine option.
• Click Continue until you’re prompted to Select a Backup Source.
• Select your Time Machine drive as the source and click Continue.
• In the Select A Destination window choose your Mac’s hard drive.

Wait for the restore to be performed. It could take several hours if you have hundreds of gigabytes of data.

Restart your Mac, as needed, and then login to your restored user account.