[Full Guide] How to Back Up Mac to an External Hard Drive

Wendy Wu
Last updated: Jan 29, 2024
Summary: This post gives you a detailed introduction to the methods to back up your Mac to an external hard drive. Keep reading and figure out what to do.

Wondering how to back up Mac to external hard drive? There are mainly 3 ways:

  1. Drag your files, photos, documents, etc. to your external hard drive manually.
  2. Back up your Mac to an external hard drive with Time Machine.
  3. Restore a volume from another volume.

Read on for the step-by-step guide.

Back up Mac to an external hard drive

What to Do Before Backing Up Your Mac to an External Hard Drive

With time, your Mac may accumulate a lot of software, files, pictures, etc. Some of them are useless, and these useless software, files, etc. can slow down your backup progress. Let alone it takes up a lot of space.

So it's necessary to clear unwanted files and software before backing up. You can do this manually, but it can be time-consuming. In this case, using third-party Mac cleaning software can save you a lot of time.

Here we recommend one of the best Mac cleaners - BuhoCleaner. It is professional and powerful. With it, you can uninstall unwanted software, remove duplicate files, remove large files, etc. in just a few steps.

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Clean Up Mac Using BuhoCleaner

Once you have cleaned up the useless software and documents, you can start backing up your Mac.

How to Back Up Mac to External Hard Drive Manually

In the case that there are a small number of files to back up, you can simply back up manually. And manual backup does not result in data loss.

Here's how to back up your Mac to an external hard drive manually:

  1. Connect your external hard drive to your Mac.
  2. Open Finder>Find and click your external hard drive on the left menu.
  3. Find the files you want to back up>Copy the files you want to back up (Command+C)>Paste the files to your external hard drive (Command+V).
Tip
To copy multiple files at once, you can click on one file first>Hold down the Command key>Click on the other files you want to select one by one.

The manual backup way is not convenient if you keep updating your files regularly. Each time you update your documents, you need to back up one more time.

So, if you want an automatic and full backup, just skip to the introduction of backing up Mac with Time Machine.

Note
The process of dragging files into your external hard drive will not work if the formats do not match. So before manually backing up your Mac to an external hard drive, you need to check if the format is right. If not, convert the format first.

How to Back Up Mac to External Hard Drive with Time Machine

Back Up Mac with Time Machine

In the case that there are multiple files to back up or for a full backup, it’s more convenient and time-saving to use Time Machine. Time Machine can automatically back up your personal data, including apps, music, photos, emails, and documents at once, saving you from tedious steps.

It’s worth noting that the first backup can be time-consuming. So before backing up with Time Machine, you are supposed to clear unnecessary files as we mentioned previously, which will save you a lot of time while backing up.

Note
It is recommended you use a backup disk that has at least twice the storage capacity of every disk or volume you’re backing up.

Part 1. Erase/Format Your External Hard Drive

Before backing up, you should check if your external hard drive is blank and in the right format. If not, you should erase your disk data and change the format using Disk Utility first.

You may encounter the following problems during the backup process:

  • Time Machine asks you to erase your external hard drive
Erase External Hard Drive in Time Machine

If you have data on your external hard drive, Time Machine will ask you to erase your hard drive before backing up, which will delete all the data on your external hard drive. To prevent data loss, we recommend that you back up the important files on your hard drive first.

In this case, you can manually erase your disk data. Or you can wait for the Time Machine to ask you to erase data and just click Erase.

  • Your external hard drive is in NTFS format and Time Machine cannot recognize it for backup

If your hard drive is in NTFS format, you will need to use Disk Utility to convert your external hard drive to a matched format such as APFS before you can use Time Machine to back up.

Here's how to erase your external hard drive and covert the format using Disk Utility:

  1. Connect your external hard drive to your Mac.
  2. Open Disk Utility using Spotlight or Finder>Find and click your external hard drive.
  3. Click Erase on the right of the top navigation.
  4. Choose the right format and click Erase.
    Erase External Hard Drive in Disk Utility
  5. Wait for the erase process to be completed.
Note
On Mac, NTFS is read-only. If you want to use a read-write NTFS format, then you will need to use third-party software such as BuhoNTFS.

Part 2. Back Up Your Mac with Time Machine

After erasing or formatting your external hard drive, you can back up your Mac to your external hard drive using Time Machine now. (During the backup process, make sure you connect your external hard drive to your Mac all the time.)

Here is the backup tutorial:

  1. Open System Settings>General>Time Machine.
  2. Click Add Backup Disk>Set Up Disk.
    Set Up Disk
  3. Wait for the backup process to be completed. (If your external hard drive has data, then Time Machine will ask you to erase it. In this case, just erase it and wait for the backup process to be completed.)

The backup process may vary from macOS versions. If your Time Machine interface is like the picture below, you can also back up your Mac by performing the actions below:

Back Up Mac with Time Machine

System Preferences>Time Machine>Select Disk>Click your external hard drive’s name>Use Disk>Click Erase if your external hard drive has data>Check Show Time Machine in menu bar>Click the Time Machine icon on the top Mac Menu>Back Up Now.

Note
Time Machine will automatically make hourly backups for the past 24 hours, daily backups for the last month, and weekly backups from all previous months. And it will automatically delete the oldest backups when your backup disk is full.

How to Restore a Volume from Another Volume

Besides the two methods we mentioned above, there is another way to back up your Mac to an external hard drive. However, this way may be a little complex.

And it is more suitable for users who have two volumes. In this case, you can restore a volume from another volume.

Conclusion

In this post, we provide you with two of the most practical ways to back up your Mac to an external hard drive. And another complex way is also mentioned briefly. The methods vary from the number of your files and the actual situations.

In addition, if you want to learn more such as how to back up a Mac without Time Machine, you can learn how to back up Mac to iCloud.

Hope this post helps you successfully back up your Mac to an external hard drive. Go ahead and back up your Mac now!

Wendy Wu is a tech enthusiast with a deep passion for all things iPhone, iPad, and Mac. Wendy is always on the lookout for Apple products and is committed to providing Apple users with some of the latest information and useful tips.