Time Machine can encrypt your Mac backups so other people cannot access the backed-up files without the encryption password. You can turn on encryption when setting up a new backup disk, or encrypt an existing backup disk from macOS settings or Finder.
The exact steps depend on whether the disk is new, already used for Time Machine, or formatted for another purpose. Before changing anything, make sure you have a current backup and that you understand whether macOS will need to erase the disk.
Quick Answer
To encrypt a new Time Machine backup:
- Connect the external drive to your Mac.
- Open System Settings and select General > Time Machine.
- Add or select the backup disk.
- Turn on Encrypt Backup if the option appears.
- Create and confirm an encryption password.
- Start the backup.
For an existing backup disk, select it in Time Machine settings and look for an encryption option. If macOS cannot encrypt the existing disk in place, you may need to erase it, format it correctly, and start a new encrypted backup.
Before You Encrypt a Time Machine Backup
Encryption protects the contents of the backup if the external drive is lost or stolen. It does not protect you if someone knows your Mac login password, your Time Machine encryption password, or the password for an account with access to the backup.
Keep these points in mind:
- Do not forget the encryption password. Apple cannot recover it for you. Without it, you may be unable to restore files from the backup.
- The first encrypted backup can take time. The initial backup may take much longer than usual because macOS must write and encrypt your files.
- The disk may need to be erased. Some existing Time Machine disks cannot be converted to encrypted storage without deleting the current backup.
- Do not disconnect the drive during setup or the first backup.
- If you are using a laptop, connect the power adapter.
- Do not proceed if you have important files that exist only on the backup disk. Copy them elsewhere first if erasing the disk is required.
Encryption is especially useful for a portable drive that could leave your home or office. It is also a sensible precaution for any backup containing personal documents, financial records, photos, or work files.
Method 1: Encrypt a New Time Machine Backup Disk
This is the simplest method because the disk has not yet been used for backups.
1. Connect the external drive
Connect the external hard drive or SSD directly to your Mac, or connect it through a reliable hub or dock. Wait for macOS to recognize it.
If macOS asks whether you want to use the disk with Time Machine, you can continue from that prompt. Otherwise, open Time Machine settings manually.
2. Open Time Machine settings
On current versions of macOS:
- Select the Apple menu in the upper-left corner.
- Open System Settings.
- Select General in the sidebar.
- Select Time Machine.
Select Add Backup Disk or the button used to add a backup disk, then choose the connected drive.
3. Turn on backup encryption
When macOS displays the setup options, select Encrypt Backup if it is available.
You may also see an option to exclude the disk from automatic backups. Leave that option turned off if you want Time Machine to back up your Mac automatically.
4. Create an encryption password
Enter a password, enter it again to confirm, and add a password hint if macOS offers one.
Use a password that is difficult for other people to guess but that you can reliably retrieve later. Store it in a trusted password manager or another secure location. Do not rely only on memory.
This password is separate from your Mac login password. It protects the Time Machine backup itself.
5. Confirm the disk and begin the backup
Confirm the selection and allow Time Machine to prepare the disk. The initial backup may begin automatically.
Keep the drive connected until the backup finishes. You can check progress in System Settings > General > Time Machine. Avoid shutting down your Mac or disconnecting the disk while the first backup is in progress.
Method 2: Encrypt an Existing Time Machine Disk
If a disk already contains Time Machine backups, macOS may let you enable encryption without erasing it. The available controls vary according to the disk format, how the disk was configured, and the macOS version.
Try Time Machine settings first
- Connect the Time Machine disk.
- Open System Settings.
- Select General > Time Machine.
- Select the backup disk or its information button.
- Look for an Encrypt Backup option.
- Follow the onscreen instructions to create an encryption password.
If the option is available, keep the disk connected and allow macOS to complete the conversion. Do not use the drive for other tasks during this process.
Check the disk in Finder
In some setups, you may be able to manage encryption from Finder:
- Open Finder.
- Select the external disk in the sidebar.
- Control-click the disk, or click it while holding the Control key.
- Look for Encrypt or an equivalent encryption option.
If Finder offers to encrypt the disk, follow the prompts and create a password.
Do not select Erase unless you are intentionally deleting the existing backup. Erasing removes the data on the disk, including previous Time Machine backups.
If the existing disk cannot be encrypted in place
You may need to create a new encrypted backup instead. This is the safest process:
- Obtain another external drive with enough capacity for your Mac’s data.
- Create an encrypted Time Machine backup on the new drive.
- Confirm that the new backup completes.
- Test that you can access the backup or restore a nonessential file.
- Only then decide whether to erase or repurpose the old disk.
If you have no second drive and the current backup contains important data, do not erase it until you have another copy.
Method 3: Erase and Reformat the Disk as Encrypted Storage
This method is useful when macOS does not offer an in-place encryption option or when you are preparing a disk exclusively for Time Machine. Erasing the disk permanently deletes everything on it.
Before starting:
- Copy any files you need from the disk.
- Verify that you have another copy of important backups.
- Make sure the correct external disk is selected.
- Connect your Mac to power if it is a notebook.
1. Open Disk Utility
- Open Finder.
- Select Applications in the sidebar.
- Open the Utilities folder.
- Open Disk Utility.
- In the menu bar, select View > Show All Devices.
Showing all devices helps you identify the physical external drive rather than only a volume stored on it.
2. Select the correct physical disk
In the sidebar, select the external drive itself. Check its name and capacity carefully. Do not select your Mac’s internal storage.
Click Erase. If Disk Utility warns that erasing will delete data, stop and verify that you have selected the right disk and preserved anything you need.
3. Choose an encrypted format
Enter a name for the disk. For the format, choose an encrypted APFS option if it is available and appropriate for your Mac. Choose the GUID partition map scheme when Disk Utility provides a Scheme menu.
Click Erase, then create and confirm an encryption password when prompted.
This formats the disk as encrypted storage. It does not yet create a Time Machine backup.
4. Select the disk for Time Machine
After Disk Utility finishes:
- Open System Settings.
- Select General > Time Machine.
- Add the newly formatted disk as the backup disk.
- Confirm that encryption is enabled or that the disk’s encryption is being used.
- Start the first backup.
If Time Machine asks to erase or reconfigure the disk again, read the warning carefully. Do not continue if you are unsure whether the action will remove data.
How to Confirm That Encryption Is Enabled
There are several practical ways to check the setup:
- Open System Settings > General > Time Machine.
- Select the backup disk or its information button.
- Look for wording that indicates the backup is encrypted.
- In Finder, select the disk and review its information if macOS displays an encryption status.
- Eject the disk, reconnect it, and check whether macOS requests the encryption password before allowing access.
A password prompt after reconnecting the disk is a useful sign, but it is not a substitute for checking the disk’s settings. If you are unsure, avoid assuming that a password-protected Mac account automatically means the backup disk is encrypted.
How to Use an Encrypted Time Machine Backup
Time Machine works normally after encryption is enabled. Keep the backup disk connected when you want automatic backups to run.
To restore files, macOS may ask you to unlock the backup disk or enter its encryption password. You can then browse older versions of files and restore them. For a step-by-step restoration process, see How to Restore Files from a Time Machine Backup.
If the disk is disconnected, Time Machine cannot create new backups to it. Reconnect it and allow the backup process to resume.
Troubleshooting Encrypted Time Machine Backups
The encryption option does not appear
The disk may already use a format that does not support the required conversion, or Time Machine may be managing it in a way that prevents in-place encryption.
Try these steps:
- Confirm that you selected the correct disk in System Settings > General > Time Machine.
- Check whether Finder offers an Encrypt option for the disk.
- Copy important data elsewhere.
- Prepare a new encrypted disk instead of erasing the existing one.
Do not erase the disk just to make the option appear unless you have another copy of its data.
The backup password is lost
There is no reliable way to bypass the encryption password. Search your password manager, written recovery records, or another secure location where you may have stored it.
Do not erase the backup disk until you have confirmed that you no longer need its contents. Erasing creates a usable disk again, but it permanently removes the encrypted backup.
Time Machine asks for the password repeatedly
Check that you are entering the Time Machine encryption password rather than your Mac login password. Then try the following:
- Eject the disk from Finder.
- Disconnect it safely.
- Reconnect it directly to the Mac instead of through a hub.
- Enter the password when prompted.
- Check the disk for errors in Disk Utility.
Repeated prompts can also result from a damaged disk, an unreliable cable, or a connection that keeps dropping.
The first encrypted backup is very slow
The initial backup has more work to do than later backups. It must copy the existing data and encrypt it as it writes the backup.
Keep the Mac connected to power, leave the disk connected, and avoid running demanding tasks until the backup finishes. If progress stops completely for an extended period, check the disk connection and review Time Machine’s status.
The disk is not available in Time Machine
Make sure the disk appears in Finder and Disk Utility. If it does not:
- Try another cable or port.
- Connect the disk directly to the Mac.
- Check whether the drive has power.
- Eject other removable disks if the system is having trouble identifying devices.
- Open Disk Utility and check whether the disk needs to be mounted.
If Disk Utility reports serious errors or the drive disconnects repeatedly, consider replacing the disk rather than trusting it with your only backup.
You accidentally selected Erase
Stop immediately if the erase process has not started. If erasing has completed, do not continue using the disk until you determine whether data recovery is necessary. Avoid writing new data to it, because new data can make recovery more difficult.
Frequently Asked Questions
Does encrypting Time Machine delete my existing backups?
Not always. macOS may support encrypting an existing disk without erasing it. However, some disks must be erased and reformatted first. Read every warning before continuing and keep another copy of important backups.
Is the Time Machine encryption password the same as my Mac password?
No. They can be the same if you choose, but they serve different purposes. The Time Machine password unlocks the encrypted backup disk.
Can I restore a Mac from an encrypted Time Machine backup?
Yes, provided you have the backup password and the disk is readable. You may need to unlock the disk before Migration Assistant, macOS Recovery, or Time Machine can access its contents.
Can I change the encryption password later?
The available options depend on how the disk was encrypted and how macOS manages it. If you cannot change it directly, create a new encrypted backup with a new password rather than risking access to the existing backup.
Should I encrypt a Time Machine backup?
Encryption is a good choice when the backup contains private information or the drive could be lost, stolen, or accessed by other people. The main tradeoff is that losing the password can mean losing access to the backup.
Does encryption protect against every type of data loss?
No. Encryption protects the backup from unauthorized access. It does not protect against a failed drive, accidental deletion, fire, theft of both the Mac and backup, or a forgotten password. Keep important data in more than one location.
Final Thoughts
The safest way to encrypt a Time Machine backup is to enable Encrypt Backup when setting up a new disk. For an existing disk, try Time Machine settings or Finder first, but be prepared to create a new backup if macOS requires the disk to be erased. Save the encryption password securely, keep the drive connected during the first backup, and verify that you can unlock the backup before relying on it.