How to Move Time Machine to a New Backup Drive

Upgrade your external storage without losing any data

iMac with Time Machine logo
Apple Inc.

Eventually, you may decide you need more room for your Time Machine backups and want to move them to a larger drive. You may need more room for two reasons. The amount of data you store on your Mac has no doubt grown over time as you added more applications and created and saved more documents. At some point, you may outgrow the amount of space available on your original Time Machine hard drive.

The other reason for needing more room is a desire to store more data history. The more data history you store, the farther back in time you can retrieve a file. Time Machine saves multiple generations of documents or other data as long as you have enough room to accommodate them. However, when the drive fills up, Time Machine purges older backups to provide room for the most current data.

These instructions apply to devices running macOS 10.6 and later.

Selecting a New Time Machine Drive

With a Time Machine, drive size is more important than overall performance. Drive speed shouldn't matter for a backup drive that you're mostly using to store data without retrieving it, so you should look for the most storage you can afford.

External enclosures are an excellent choice for Time Machine drives, allowing you to connect the drive to your Mac using Thunderbolt or USB 3 depending on your needs. USB 3 and later enclosures are by far the most popular and the least expensive of the enclosure options, and they are a good value for this use. Just make sure the enclosure is from a reputable manufacturer.

Moving Time Machine to a New Drive

Follow these steps to move your current Time Machine backup to a new, larger drive.

  1. Connect the new hard drive to your Mac, either internally or externally. External drives can connect to a USB, Thunderbolt, or FireWire port on the Mac.

  2. Start up the computer.

  3. Time Machine works with drives in Mac OS Extended (Journaled) formats and Xsan formats. If the backup drive you attach isn't compatible, the Mac will prompt you to erase it. With some OS versions, the Mac prompts you to reformat at this step. If not, you can format the drive using Disk Utility.

    Formatting the hard drive erases any data it contains.

  4. How you use Disk Utility to format your new hard drive depends on which edition of macOS you're using. The instructions are different for versions up to and including Yosemite and ones since El Capitan.

  5. Once you finish formatting the new hard drive, it mounts on your Mac's desktop.

  6. Right-click the new hard drive icon on the desktop and select Get Info from the pop-up menu.

    Get Info option for an external hard drive on a Mac
  7. Make sure that Ignore ownership on this volume isn't active. To change it, click the padlock icon located in the bottom right corner of the window.

    Get Info window with the padlock icon highlighted
  8. When prompted, supply an administrator's username and password. You can now make the changes.

  9. Click the padlock again to save your changes.

Transferring Your Time Machine Backup to a New Hard Drive

Once you've set up the new drive, you'll need to transfer your old Time Machine backups to it. Here's what to do.

  1. Launch System Preferences by clicking the System Preferences icon in the Dock, or selecting System Preferences from the Apple menu.

    System Preferences under a Mac's Apple Menu
  2. Select the Time Machine preference pane.

    System Preferences on a Mac with the Time Machine icon highlighted
  3. Slide the Time Machine switch to Off or remove the checkmark from the Back Up Automatically box. Both perform the same function.

    Time Machine settings on a Mac with the
  4. Connect your original drive to your computer and drag the Backups.backupdb folder to the new drive.

    A backup drive on a Mac with the Backups folder highlighted
  5. If asked, supply an administrator name and password. The copying process can take a while, depending on the size of your current Time Machine backup.

  6. Once the copying is complete, return to the Time Machine preference pane and click Select Disk.

    Time Machine preferences on a Mac with the Select Disk button highlighted
  7. Select the new disk from the list and click Use for Backup.

    Time Machine Select Device screen with the Use Disk button highlighted
  8. Set the Time Machine switch to On or check the box in front of Back Up Automatically.