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How to Speed Up Your Initial Time Machine Backup

By November 23, 2016Tutorials

When Apple brought Time Machine to the Mac, it made it so much easier to backup your computer to an external disk. They made it extremely easy by keeping automatic backups every hour, daily backups for the past month, and weekly backups for previous months. You basically set it up and forget about it. However if your external hard disk is connected to an AirPort Extreme, you’ve probably discovered that the initial backup can take a LONG time. If you have hundreds of gigabytes of data, it could easily take over a day to complete the backup. I’ll show you a technique that will enable you to do the initial backup locally, that will turn days into hours.

I.  Partition the Backup Disk

  1. First you’ll need to make certain your backup disk is using the correct partition for Mac OS to recognize. Connect your backup disk to your computer.
  2. Open Disk Utility and click on the backup disk you just connected on the left:
    Disk Utility
  3. You’ll want to be certain your disk is formatted using Mac OS Extended (Journaled). If not, click the “Erase” button at the top and type a name you prefer to use, and the corresponding Format. You can leave the Security Options alone.
  4. Once it has completed formatting, eject the disk from your computer.

II.  Prepare the Disk on your AirPort Extreme

  1. Now we need to prep the files on the backup disk before we can do the backup locally. Connect the backup disk to your AirPort Extreme.
  2. We need to tell the AirPort Extreme which backup disk to use. Open AirPort Utility and go into your AirPort Extreme disk settings:
    AirPort Utility
  3. Make sure that the disk you just formatted is selected. Close AirPort Utility.
  4. Now we need to open a finder window and let Mac OS recognize the external hard disk. So open the Finder and select your AirPort Extreme on the left in the Shared drives section:
    Finder Window
  5. Click the Connect As… button on the top of the window and you’ll be asked to enter your AirPort Extreme password.
  6. Double click the shared folder inside AirPort Extreme. This should be the name you used to format your backup disk.
  7. Now that the disk is recognized, we need to select it in Time Machine. Open Time Machine.
  8. Click the Select Disk… button and click the name of backup disk you connected to AirPort Extreme:
    Time Machine Settings
  9. Click the Use Disk button. Uncheck the “Back Up Automatically” for now.
  10. It will begin prepping the files on the disk:
    Backing Up
  11. Wait until it begins writing actual data onto the disk. Once this begins, you can go ahead and cancel the backup by clicking on the gray X.
  12. If you look in the Finder, you’ll notice it has created a backup file on our drive:
    Backup File
  13. Go ahead and eject your AirPort Extreme drive in the list of shared drives on the left.

III.  Complete a Local Backup

  1. Unplug your backup disk from your AirPort Extreme and plug it back into your computer.
  2. Inside Time Machine make sure your backup disk is selected as the drive to use and make sure to uncheck “Back Up Automatically”. We’ll turn this back on later.
  3. On the Mac OS menu bar, click on the Time Machine icon, then click “Back Up Now”. This will do a complete backup of your computer locally. Depending on how much data you have, will determine how long this will take. It will take a few hours. Go grab some coffee.
  4. After this has completed, eject the backup disk.

IV.  Move the Backup Disk back to the AirPort Extreme

  1. Plug the backup disk back into the AirPort Extreme.
  2. Select the drive again inside Time Machine.
  3. Make sure “Back Up Automatically” is now turned on.
  4. That’s pretty much it! It will now complete incremental backups over your network as usual. You can click the Back Up Now button in the menu bar to be certain it works.


  • Chris Rimple says:

    I’ve done this successfully in the past, but now having issues. I’ve got a new backup drive, formatted correctly, and I’ve connected it to my Airport Extreme. I select it and start backups from 3 machines: one Mac Mini that is hardwired (ethernet) to the Airport, and two Macbook Pros that are connected via wifi. When opening the Airport from Finder, I see “Backups” (external drive volume name), and a “Mac Mini” sparsebundle file, but I also see the MBP files as “LaptopA.sparsebundle” and “LaptopB.sparsebundle”, as if the difference in wired/wireless has caused a file naming/extension hiding difference. I can connect the drive to the Mac Mini, select it, and the full backup is written to the “Mac Mini” file – same for the laptops, to the “*.sparsebundle” files. BUT, when I later attempt backups with the drive connected to the Airport, the Mac Mini (wired) backup is fine, while the (wireless) laptops create NEW sparsebundle files and ignore the existing ones. Perhaps it’s because, when selecting the remote drive for backup from Mac Mini, it shows as “Backups on Networkname” and when selecting from the laptops it shows as “Backups on Networkname.local”? Any idea how to correct this?

    • Oh man I have no idea with this one! 3 different machines might be a little more tricky. I’d recommend visiting MacOS Support, and let them know your issue. They’re usually pretty good about helping with stuff like this!

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