How and when to clone Mac hard drive for safekeeping
A clone of your Mac is essentially a backup of all the data you can make bootable, so when you connect the disk to another Mac, you just reboot and carry on from where you left off.
Cloning your Mac’s main drive is a great way to protect yourself against potential problems when doing things like installing a new or updated version of macOS — especially if you’re using a beta version of macOS. Clones can also be useful during travel if you’re worried that your Mac might get lost, stolen, or damaged.
When you need to recover files from a failing system, having a clone of your hard drive helps you recover files, eliminating the possibility the failing drive will die completely before files are recovered.
Cloned backups differ from the now popular ‘incremental backup’ as a clone creates a snapshot of your Mac that is preserved for as long as you want, whereas incremental backups update themselves at regular intervals and replace older versions.
The difference between cloning and using Time Machine
As noted above, a clone is an ‘image’ of your hard drive, meaning it’s a compressed version of your entire hard drive you can revert to at any time.
Time Machine is Apple’s default method for creating incremental backups. Time Machine keeps the latest versions of a backup on your Mac, which is meant to give you the most recent ‘image’ when you buy a new computer or need to do a factory reset on your Mac. The goal is to get you back up and running quickly.
The issue is you don’t control incremental backups, and can’t define which backups are kept. Out Time Machine, for example, backs up automatically every other day or so, and keeps the last dozen-ish images. If we needed to revert to a backup from several months ago, Time Machine wouldn’t work for us.
Cloning is great for those who need control, especially for businesses that may need to clone drives with sensitive business data like tax info or client files. This is why we advocate for pro tools like Disk Drill, which allow you total control over when backups are created, which files or folders are included in a backup, and offers dense compression of backups. It’s really simple to use, too!
How to create a clone of your Mac
There are a few things you need to do when you want to clone Mac hard drive and use it as a backup. First, you need an external hard drive or SSD with a volume that’s clean and empty, which means it should either be brand new or completely erased beforehand.
Next, you’ll need software to create the clone. There are several applications that are available for Macs that you can use. We recommend going with Disk Drill. Disk Drill can help you recover data from a failed drive and allows you to create byte-for-byte copies of a disk and save them as a disk image. In other words — clone your Mac.
Finally, you need a safe place to store your clone — a backup is no good if you can’t find it when you need it.
Before you start
If you have a regular backup routine, it’s a good idea to run one before you start the process of cloning your Mac. It sounds daft to run a backup just before you create a backup, but it’s always better to be safe than sorry. If you’re using a disk that’s been used before, you’ll need to erase it completely to make it ready for the clone. We’ll assume you’re going to use the whole disk as a single volume.
If you don’t already use it, try Get Backup Pro to manage your backups. It can create full or incremental backups, sync folders across multiple Macs, and create bootable clones for new computers or reboots. You’re also able to schedule backups whenever you like, and save them to any external drive.
How to prepare your SSD or any other external drive to use for your clone
Before we tell you how to clone a hard drive Mac for use as a backup, you need to prepare a place for the clone to live. A popular option is using an external drive, preferably an SSD drive, which is less prone to failure.
To clone Mac hard drive to SSD drives you first have to format the drive you want to use. This external drive should also be used exclusively as a repository for a clone of your Mac. If you want to save several backups, be sure to buy a larger external drive, or several smaller ones. That part is entirely up to you.
Before you clone hard drive to SSD Mac requires that you dive into Disk Utility and erase that external drive. Plug the external hard drive into your Mac, and launch Disk Utility. Go to the Utilities folder in Applications and double-click on Disk Utility to open it. To clone Mac hard drive Disk Utility is Apple’s built-in solution.
Erase the drive. Click on the external drive in the sidebar and then the Erase tab. In most cases, the format will automatically be set to macOS Extended and the scheme to GUID Partition Map. You can leave it at that. If you’re running macOS Mojave and will only use the drive with a Mac using Mojave, you can choose APFS from the Format menu. Give your drive a name and click Erase.
From there, you will want to use Disk Drill, one of the best Mac hard drive clone software options around.
Create a disk image of your drive
Here’s a step by step guide to create a disk image using Disk Drill:
- Open Disk Drill on your Mac
- Connect your external drive to your Mac
- Select “Backup” in the toolbar
- Choose “Backup into DMG Image”
- In the popup window, select “OK, Let’s Do It”
- Choose your Mac’s boot disk (typically “Macintosh HD”)
- Select “Backup”
- When asked where you want to save your backup, select the external drive
- Select “Save”
Disk Drill will now create an exact copy of your boot drive as a disk image, saved on the external drive, and that’s how you clone external hard drive Mac.
Once the disk image has been created, you can double-click on it to mount it in the Finder. It will then be treated like any other volume by macOS and you can drag and drop files from it to your main drive. That’s fine if you only lose a few files and folders and need to recover them, but what if your boot drive fails or you need to recover the whole disk from the image?
Restore the clone
You can’t boot a Mac from a disk image, but you can restore the clone to your Mac’s boot drive if you need to. Here’s how.
- Shut down your Mac
- Restart in recovery mode. Restart your Mac while holding down the Command and “R” keys.
- Erase your boot drive. Click on Disk Utilities in the Utilities application and then Erase. If the disk image you’re restoring from has macOS High Sierra installed, choose APFS from the format menu, otherwise, choose macOS Extended (Journaled). Give it a name and click Erase.
- Restore the disk image. Still in Disk Utility, click on the drive you just erased. Now go to the File menu and choose Restore. Click the Image button and navigate to the disk image you created in Disk Drill. Then Restore.
Alternatively, if you know beforehand that you’re going to need to boot from the clone, choose Create Boot Drive and then Boot Drive for data recovery instead of Backup when you've created the disk image of your drive.
Recover files from disk image
If you don’t need to completely replace your Mac’s startup disk, but need to recover files from a disk image — perhaps because you created the image from a failing drive that has now failed completely — you also can do that in Disk Drill.
- Mount the drive. Double-click on the disk image in the Finder to mount it.
- Recover data in Disk Drill. Select the mounted volume in Disk Drill’s main window and click Recover. Follow the on-screen instructions to scan the volume, identify and recover the files you need. Remember that you should never recover files to a failing hard drive, so choose a destination that you know is stable.
Bonus Tip: How to keep your Mac clean?
Keeping your Mac clean is important. It helps your Mac run smoother, and allows your clones to be organized for an optimal starting point when you need to reboot from a backup.
CleanMyMac X is the best tool for keeping your Mac running at peak performance. It can run routine scans, and is a great way to delete apps or files you no longer need. It removes clutter from your Mac and keeps it running smooth.
Another great app to download is iStat Menus, a system monitor that lives in your menu bar and provides insight on your CPU, GPU, and RAM use as well as your battery health statistics and various other tidbits you’ll want to keep track of, like how hot your computer gets.
Backups are really important, even if you only create them every few months. Incremental backups are good, too, but when you’re trying to recover files from months ago, this method likely fails you.
All of the apps we mentioned today – Get Backup Pro, CleanMyMac X, Disk Drill, and iStat Menus – are available for free as part of a 7-day trial of Setapp, a suite of nearly 200 excellent Mac apps. When your trial is over, Setapp is only $9.99 per month, an excellent bargain when you consider the number of apps you will have access to. Give Setapp a try today!