Prepare a new hard drive for Time Machine
- Make sure the drive is on. Click on Spotlight, the little magnifying glass at the top right of your computer screen
- Type “disk”
- Double-click on Disk Utility
- In the left sidebar of Disk Utility, you should see a line with the generic volume name and thumbnail of your external drive, e.g. “LaCie” or “WD” probably with a yellow icon. Click that line
- Click the Erase button on the right
- Set the Name to “Backup” (if you like, put your name in there too)
- Set the Format drop-down menu to “Mac OS Extended (Journaled)” if it’s not already
- Click the Erase button
- You’ll be asked if you’re sure. Yes, you are sure.
Now, if you haven’t previously chosen a Time Machine backup, your Mac may ask if you want to use the new volume for backup. Say yes. If it doesn’t:
- Go to Apple menu > System Preferences > Time Machine
- Click Select Disk
- If there’s a lock at the bottom left of the window, unlock it with your password
- Click the Options button at bottom right. If there are any items listed under “Exclude these items from backup,” remove all of them except for the grayed-out “Backup” drive
- Click Save
- Click on “Backup” (or whatever you called your drive)
- Click Use Disk.
Time Machine will start backing up your computer. It will give you a broad idea of how long it will take. Whether it’s a couple of hours or overnight, just leave it until it’s done. From then on, Time Machine will continue to back up the entire computer every hour.