Disk Utility’s Restore function can be used to copy the content from one volume to another. In this respect, it’s similar to the process of cloning a volume, and indeed, the Restore function can be used to create bootable clones. But if this is your primary reason for using the Restore function, I recommend the use of dedicated cloning apps, such as Carbon Copy Cloner or SuperDuper, that have a great deal more features that are highly serviceable in the cloning process.
The Restore feature can also be used to copy disk images to a target volume, restore an image of your startup volume, or simply copy the content of one volume to another.
We’ve already covered the basics of using the Restore feature for cloning in the Rocket Yard article: Tech Tip: How to Use the Restore Feature of Disk Utility to Clone a Drive.
In this guide, we’re going to look at how Disk Utility’s Restore feature has changed in macOS High Sierra; specifically, the new support for APFS containers and volumes, and how they bring new capabilities as well as limitations to how you restore data from one storage device to another.
What Hasn’t Changed in the Disk Utility Restore Function
The basic concept remains the same; you use Disk Utility to select a destination volume from the sidebar, and then choose a source to copy from. Once the copy (Restore) starts, the destination device is unmounted and erased, and the content from the source is copied to the new location. Once the copy is complete, the destination is mounted, and you’re ready to make use of the information.
Restore can also make copies of disk images, as well as just about any device that can be mounted on the Mac’s Desktop. This means you can make copies of just about anything you wish, including creating archives of videos from your camera’s flash drives before you perform any type of edits, creating clones before upgrading an OS or important app, and just as important, being able to return to a known good state should something befall an upgrade.
Warning: The destination volume you select from the sidebar in all of the restore processes outlined below will have all of their contents erased. Make sure you have valid backups before trying any of the restore instructions.
Restore Basics: Copy a Volume
Launch Disk Utility, located at /Applications/Utilities.
Select a destination volume formatted with the HFS+ file system from the Disk Utility sidebar.
You can tell the format by looking at the description just below the device’s name in the main Disk Utility panel. As an example, when I select my startup volume it shows up as a standard HFS+ volume: Macintosh HD SATA Internal Physical Volume, Mac OS Extend (Journaled).
APFS volumes, on the other hand, will say Volume Name APFS Volume . APFS (or they could say APFS Encrypted).
With an HFS+ volume selected as the destination, click the Restore button in the toolbar, or select Restore from the Edit menu.
A sheet will drop down asking if you would like to restore to “the selected device name”? Just below is a description of what will occur, including a warning that the destination device will be erased during the process.
From the dropdown sheet use the dropdown menu to select a source to be used to copy data from.
When you’re ready, click the Restore button.
The restore process will start and a new sheet will appear with a status indicator. When the copy is complete, the status indicator will have filled up and you can click the Done button.
Restore Basics: Copy From a Disk Image
This process follows the same steps: select a destination volume from the Disk Utility sidebar, and then click on the Restore button in the toolbar.
At this point, the Restore dropdown sheet is asking you to use the dropdown menu to select a source. Instead of using the dropdown menu, click the Image button just to the right of the menu.
A standard Finder Open window will appear; navigate to the disk image file you wish to use as the source. Disk Image files usually end in .dmg. Once you locate the disk image, select the .dmg file and click the Choose button.
The Restore from dropdown menu will now contain the image file name.
When you’re ready, click the Restore button.
The restore process will begin, displaying its status bar. When it completes, you can click the Done button.
Restore Basics: Copy an APFS Volume
So far, we’ve looked at restoring when the source volume is formatted as HFS+. In this example, we’re going to select an APFS volume as the source, to see how the process works.
In Disk Utility’s sidebar, select an APFS volume. You can verify that it’s an APFS volume by reading the volume description in the main panel.
With the APFS volume selected, click the Restore button in the toolbar.
In the sheet that drops down, use the dropdown menu to select a source for Restore to use.
You may notice that only APFS volumes are being displayed in the menu’s list. Restore in Disk Utility can only use devices formatted with APFS as sources for copying to APFS formatted volumes.
Select an APFS formatted source, and then click the Restore button.
Disk Utility will display the process sheet. When the copying is complete, click the Done button.
Restore Basics: Copy APFS Disk Images
When the destination is an APFS formatted volume, only APFS formatted disk images can be selected as the source. Otherwise, copying an APFS disk image works the same way.
Select an APFS formatted source in the sidebar.
Click the Restore button in Disk Utility’s toolbar.
In the dropdown sheet, click the Image button.
Navigate to the APFS disk image you wish to use, and then click the Choose button.
The disk image name will be placed in the Restore from: dropdown menu.
When you’re ready, click the Restore button.
The status sheet will drop down, displaying the copy progress. When it’s complete, click the Done button.
Restore Advanced: Copy to Containers
Disk Utility doesn’t support using the Restore function to copy the content of a container, including any volumes it may contain. However, you can select a container as the destination for restoring.
When you select a container to restore to, all of the volumes within the selected container will be erased and a new volume containing the content of the selected source will be created.
In Disk Utility’s sidebar, select a container as the destination for a restore.
If you’re only seeing volumes in the sidebar, you can alter the sidebar settings to view containers as well by clicking on the View button in the Disk Utility toolbar and selecting Show All Devices.
With a container selected in the sidebar, click the Restore button in the toolbar.
Use the Restore from: dropdown menu to select a source for the restore. When the destination is a container, you can select any type of volume as the source, including those formatted as HFS+ or APFS.
You can also use the Image button to select a disk image to use as the source.
Once you have the source selected, click the Restore button to start the erase of the destination and the copying from the source.
Disk Utility will display a progress bar. Once the process is finished, click the Done button.
Disk Utility’s Restore function has a few limitations that may not be apparent right away. Many of these limitations are caused by the Disk Utility app itself, and not the underlying file formats being used. You may find the use of dedicated cloning apps a more versatile choice for making copies of volumes and disk images.
- When you’re restoring to an APFS volume, the source volume must also be formatted as APFS.
- When you’re restoring to an APFS container, the source volume can be any supported format, including APFS and HFS+.
- An APFS container can’t be used as the source, which prevents you from restoring multiple volumes at one time.
- Using an APFS container as the destination will cause all data within the selected container to be erased; this includes all volumes the container may house.
Common Errors and Troubleshooting
Disk Utility’s Restore feature generally does a good job, and the copying of data should go off without a hitch, providing you pay attention to the limitations mentioned above. Beyond those limitations, the most common problem you’re likely to encounter will be displayed with the following cryptic message:
Restore process has failed. Click Done to continue.
At this point, do not click the Done button; doing so will dismiss the error message as well as a log that contains details about the problem, which you can use to help fix any issues. Instead, click the disclosure arrow next to the Show Details text.
In the log that displays, the following are common errors you may see:
Size errors: Restore performs a size validation to ensure the destination is large enough to contain the source. If the log entry includes the line: Not enough space on VolumeName, then there’s a size error. Check that the size of the destination is large enough to hold all the data from the source.
Resource busy error: This error usually shows up as a log line saying: Could not restore – Resource busy. There are two common solutions; both involve ensuring that no files on the source or destination are in use at the time of the restore. In the first case, try closing all apps except for Disk Utility, and then try the restore again. If that doesn’t work, boot from another startup drive, or your Restore HD partition, and try the restore process again.
Mount or unmount errors: Within the logs there may be an error indicating failure to unmount a disk or to mount a disk. Most unmount errors are caused by files that are in active use, preventing the disk from unmounting. Try the same fixes as outlined in the Resource busy error, above.
Mount errors, on the other hand, are usually just a minor nuisance and can be corrected by selecting the volume that failed to mount from the Disk Utility sidebar, and then selecting Mount from the File menu. This should cause the volume to complete the mount process.