Choose Disk Utility in the Utilities application.Hold down Command+R while you restart your computer.This limitation is specific to Disk Utility – if you're restoring from a disk image using CCC, CCC can restore an APFS disk image to an HFS+ volume, and you can restore an HFS+ disk image to an APFS volume. Note: The destination volume format must match the format of the disk image that you're restoring from. If you do not have an installation of macOS on another hard drive, you can boot your Mac from your macOS Recovery volume and use Disk Utility to restore the entire disk image: High Sierra and Mojave Restoring system files to your startup disk when you don't have a bootable backup Once you have booted your Mac from another volume, follow the steps from the previous section. If you want to restore system files to your startup disk, you must start up your Macintosh from an installation of macOS on another hard drive, such as a bootable backup created by CCC. Restoring system files to your startup disk from the Clone menu (below the Source selector) and deselect any item that you do not wish to restore. If you do not want to restore everything, choose Some files.You may not choose the current startup disk as a destination, however you may choose to restore to a folder on the current startup disk. Choose a volume from the Destination selector.from the Source selector and locate your backup disk image. To restore files or an entire filesystem from a disk image: Restoring individual items or an entire disk image to another hard drive using CCC

If you have the permission to access the files that you would like to restore, simply drag those items to the volume that you would like to restore them to. Double-click on the disk image file to mount its filesystem, then navigate the filesystem in the Finder to access individual files and folders. You can access the contents of a disk image the same way that you access other volumes and external hard drives on macOS.

Mac disk image mounter