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Overview
Encrypt USB flash drives and external storage drives to help protect data if a drive is lost or stolen. The University's Media Protection standard requires encryption for high-risk data stored on drives. However, OIT recommends encrypting external drives whenever possible.
External drives are not approved for storing Sensitive Personal Information (SPI) or FERPA-protected data, even when encrypted.
This article explains how to encrypt an external drive using the Finder application (Mac) or enable encryption when setting up a Time Machine backup.
Sections
- Data restrictions: Do not store SPI or FERPA-protected data on external drives. See the University's Media Protection standard for data protection requirements.
- Windows and Mac compatibility: the Finder application encryption may prevent the drive from being accessed directly on Windows computers. If you need to use the drive with both operating systems, encryption may not be suitable.
- Password: Store your encryption password securely. If you lose it, you may not be able to recover your data.
- Drive format: Some formats do not support Finder encryption. Reformatting a drive erases its contents, so back up any files you need first.
- Backups: Encryption does not protect against drive failure or accidental deletion.
Use this method for USB flash drives and external drives used to transfer or store files.
- Connect the drive to your Mac.
- Open Finder and locate the drive.
- Control-click the drive and select Encrypt [drive name].
- Enter and verify a password, then add a hint if prompted.
- Click Encrypt Disk and allow the process to finish.
You may need to enter the password whenever you connect the drive before accessing its contents.
If the Encrypt option is unavailable, the drive's format may not support it. See Apple's guide to encrypting storage devices for more information.
For a drive used with Time Machine, enable encryption during setup.
- Connect the drive to your Mac.
- Open the Apple menu and select System Settings.
- Go to General → Time Machine.
- Click Add Backup Disk or the + button.
- Select the drive and click Set Up Disk.
- Enable Encrypt Backup.
- Create a password and store it securely.
- Complete setup and allow the initial backup to finish.
Important: If macOS asks to erase the drive, save any files you need first. Erasing permanently deletes its contents.
For an existing backup drive, see Apple's guide to keeping your Time Machine backup disk secure.