Mac mini (Late 2012 and later), iMac (Late 2012 and later): About Fusion Drive

Fusion Drive is a new storage option for Mac mini (Late 2012 and later) and iMac (Late 2012 and later) computers that combines the performance of Flash storage with the capacity of a hard drive.

Presented as a single volume on your Mac, Fusion Drive automatically and dynamically moves frequently used files to Flash storage for quicker access, while infrequently used items move to the hard disk. As a result you'll enjoy shorter startup times, and as the system learns how you work you'll see faster application launches and quicker file access. Fusion Drive manages all this automatically in the background.


Frequently Asked Questions

Do I need to configure Fusion Drive?
When ordered with a Fusion Drive, your iMac or Mac mini is pre-configured.

Can external USB, FireWire, or Thunderbolt hard drives be added to Fusion Drive?
An external drive cannot be used as part of a Fusion Drive volume. Fusion Drive is designed to work with an internal hard disk drive and internal flash storage.

Can I add a partition to the hard disk with Fusion Drive?
Using Disk Utility, you can add one partition to the hard disk on Fusion Drive. Once you add the partition, the "plus" symbol in Disk Utility to add additional partitions will be grayed out. You cannot partition the Flash storage.

If I create a hard disk partition is it part of Fusion Drive?
The additional partition is not part of Fusion Drive. The new partition is a separate volume that is physically located on the hard disk drive.

Can I add a Windows partition?
You can create one additional partition on the hard disk with Fusion Drive. You can create either a Mac OS X partition or a Windows partition.

If creating a Windows partition, use Boot Camp Assistant to create it, not Disk Utility. From the Go menu, choose Utilities. Then, double-click Boot Camp Assistant and follow the onscreen instructions. For more information on Boot Camp see the Boot Camp support page

Note: Boot Camp Assistant in OS X Mountain Lion v10.8.2 and earlier does not support 3TB hard drive configurations.

I receive a "disk is too small for this operation" message when creating a partition. Why?
The partition you are trying to create has a larger size than free space available on the hard disk drive. Reduce the size of the partition you are trying to create and try again.

Can a Fusion Drive be mounted on another system in Target Disk Mode?
Yes, but the system attempting to mount the Fusion Drive in Target Disk Mode must have OS X Mountain Lion version 10.8.2 or later. A Fusion Drive will not appear as a Target Disk Mode volume or startup disk on earlier versions of OS X. 

Can third-party disk utilities be used with a Fusion Drive?
Third party disk utilities may or may not work with a Fusion Drive. Check with the third-party software vendor to check for compatibility with a Fusion Drive.

I'm using video capture software and it reports frame drops during sustained captures. What could be wrong?
Your project's capture requirements may exceed the sustained capture rate available to your Fusion Drive. Try capturing a smaller segment of the source or reduce its resolution.

I've recently reset NVRAM (Non-Volatile Random Access Memory, also known as PRAM) and now my Fusion Drive is starting up more slowly. How can I fix this?
The reset removed your Startup Disk setting from NVRAM. To access the setting, choose System Preferences from the Apple () menu. Then, click Startup Disk and then Macintosh HD. Note: You may have to click the lock icon at the bottom of the window and enter your system administrator password to manage this setting.

How can I restart into OS X Recovery on a Fusion Drive Mac?

  1. Shutdown your computer.
  2. Press the power button to turn it back on, and then press and hold Command-R until you see the OS X Recovery screen. 
  3. Select the Recovery HD. 

For more information see OS X: About OS X Recovery.

Learn more


  • The version of Disk Utility that comes with Fusion Drive is unique. Earlier versions of Disk Utility can't be used with a Fusion Drive.
  • If your system will not start because you see a flashing question mark or another alert:

    1. Press the Power button and hold it down to power off your system.
    2. Press the Power button again. After you hear the startup chime, press and hold Command-Option-R to start up to the Internet version of OS X Recovery.
    3. A globe should appear with a "Starting Internet Recovery" message. It is now OK to release Command-Option-R.  
    4. A progress bar should appear and Internet Recovery should start and ask you to select a language.
    5. Once you select a language, click Disk Utility in the window that appears and then click Continue.
    6. If your Fusion Drive can be fixed with Disk Utility, you'll see a Disk icon with red lettering. Click the disk icon.
    7. A dialog box appears offering to fix the Fusion Drive (shown above). Caution: Clicking Fix will erase your Fusion Drive. If you have a Time Machine backup of your Fusion Drive Mac, see Mac 101: Time Machine for information on how to restore from a Time Machine backup once the drive has been erased.
    8. After the process is complete, the volume will change color to black. Quit Disk Utility, click Install OS X, then click Continue.

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