Time Machine is a built-in backup software application that OS X offers. It can keep a backup copy of all or selected files, and allows you to restore your whole system or specific files as they appeared in the past.
Steps to Back up Files Using Time Machine:
1. Connecting to Time Machine.
* When you connect an external hard drive (flash/thumb drive) to your Mac for the first time, Time Machine will ask if you would like to use it for backups.
* Click "Use as Backup Disk" and System Preferences will then open to display Time Machine preferences.
2. Remove Unnecessary Items to Conserve Disk Space.
* You might not need everything on your computer to be backed up. You can exclude these items by clicking on the Options button in the Time Machine preferences window and add files and folders to the "Do not back up" list by clicking the + (plus sign) button.
* You can always go back and add the excluded items to the list by clicking the - (minus) button, and those items will be included in the next backup.
* The first time your Time Machine backup starts, a new window will appear on your desktop to let you know things are going.
4. Wait for the Backup
* The first backup session will probably take a long time since everything on your Mac is being copied. After the first backup, Time Machine will automatically back up incremental changes to your files every hour for as long as you leave the backup drive connected to your Mac. Future
backups will only copy files that are new or have changed, so they'll take less time.
* In Time Machine's preferences window, you’ll see the option to show Time Machine's status in the menu bar. The Time Machine’s menu bar icons allows you to access Time Machine preferences and perform backups any time you want, so you don’t have to wait to back up important files.
5. Understanding Time Machine
* After a while, your backup drive will be full, and Time Machine will need to delete your oldest backups to make room for new ones. Time Machine will handle this automatically.
* If you accidentally delete an important file that needs to be backed up, all you have to do is click on the Time Machine icon in your Dock or the menu bar to enter Time Machine and retrieve the file. Entering Time Machine replaces the Desktop with an outer space background and Finder
windows stretching into infinity. Despite all these special effects, finding backed up files is easy.
* The front Finder window shows what is currently on your Mac. All the Finder windows behind the first one are earlier backups.
* You can navigate to the last time a file was backed up by using the arrows at the bottom of the Time Machine screen. Once you find the missing file(s) click on it, and then click the Restore button at the bottom right to copy the file from your backup drive to your Mac's hard drive.
* Because Time Machine uses a Finder window, you can navigate to any folder to retrieve files, not just what's on the Desktop.