[KB8226] Decrypt an Apple computer encrypted with ESET Full Disk Encryption

Issue

  • Recover files from disk encrypted with ESET Full Disk Encryption (EFDE) from Apple computer with macOS Catalina (10.15) or Big Sur (11)

Details


Click to expand

Due to the nature of macOS 10.15 – 11, you cannot boot to a recovery mode with Terminal on an encrypted Apple computer.

ESET provides a workaround using the Target Disk Mode, where two Apple computers are required.


Solution

  1. Download the recovery data file
  2. Create a recovery USB disk
  3. Unlock the encrypted disk from another computer
Required hardware

To complete the steps in this guide, you need a USB disk, a second Apple computer and a cable to connect the two Apple computers in Target Disk Mode (for example, a USB-C or a Thunderbolt cable, depending on your computer models).


I. Download the recovery data file

  1. Open the ESET PROTECT Web Console in your web browser and log in.

  2. Click Computers, select the computer you want to decrypt the disk and click Show Details.

    Figure 1-1
    Click the image to view larger in new window
  3. In the Encryption active dashboard, click ManageRestore AccessRecovery data.

    Figure 1-2
    Click the image to view larger in new window
  4. Type a new Password, confirm the password and click Create Recovery Data.

    Figure 1-3
    Click the image to view larger in new window
  5. To download the recovery data file, click efderecovery.dat and save or copy the file to a USB disk.

    Figure 1-4
    Click the image to view larger in new window
Identify the computer by its Workstation ID

If you can not identify the affected workstation, at the top of the management console, click HelpEncryption recovery, select Recovery data and type the Workstation ID displayed on the bottom of the EFDE pre-boot login screen.

The recovery data file is unique for each decryption

Generate a new efderecovery.dat file for every workstation you want to decrypt (even for another decryption of the same workstation).


II. Create a recovery USB disk

  1. On a second Apple computer, download the Encryption recovery tool for macOS and unzip and copy the recoveryapp file to the USB disk that contains the efderecovery.dat file

  2. Open Terminal, type cd /Volumes/[NAME], where [NAME] is the name of the USB disk and press Enter.

  3. Type the following command and press Enter:

    ./recoveryapp efderecovery.dat
  4. Type the password you created in ESET PROTECT and press Enter.

    Figure 2-1
    Click the image to view larger in new window

III. Unlock the encrypted disk from another computer

  1. Connect the Apple computer with the EFDE encrypted disk to a second Apple computer. Verify that the USB disk is inserted into the second Apple computer.

  2. Boot the Apple computer with the EFDE encrypted disk to a Target Disk Mode. To do this, shut down the computer, press the power button and then press and hold the T button on the keyboard.

    For example, if you are using a Thunderbolt connection, the screen of the Apple computer in Target Disk Mode will look like this:

    Figure 3-1
    Click the image to view larger in new window
  3. On the second Apple computer, open Terminal, type the following command and press Enter:

    diskutil apfs list

    From the list of the disks, find the partition with the description FileVault: Yes (Locked). Make a note of the partition identifier (in this case, disk15s1).

    Figure 3-2
    Click the image to view larger in new window
  4. Type the following command where [IDENTIFIER] is the disk identifier and [NAME] is the name of the USB disk and press Enter:

    diskutil apfs unlockVolume /dev/[IDENTIFIER] -recoverykeychain /Volumes/[NAME]/FileVaultMaster.keychain
    Figure 3-3
    Click the image to view larger in new window
  5. Type the password you created and click OK.

    Figure 3-4
    Click the image to view larger in new window
  6. The disk will unlock and show as a mounted disk on the desktop. You can access and copy the data from the encrypted disk.

  7. To decrypt the disk, type the following command and press Enter:

    diskutil apfs decryptVolume /dev/[IDENTIFIER] –recoverykeychain /Volumes/[NAME]/FileVaultRecovery.keychain
    Figure 3-5
    Click the image to view larger in new window
  8. To see the decryption progress, type the following command and press Enter:

    diskutil apfs list
    Figure 3-6
    Click the image to view larger in new window
  9. When the encryption is complete, you can exit the Terminal, unmount the disk (drag the disk icon to the trash bin icon), disconnect the two Apple computers and shut down and power on the Apple computer you want to decrypt to exit Target Disk Mode.

Encrypt the disk again

To encrypt the decrypted disk, run the encryption task in ESET PROTECT. If the task fails, uninstall ESET Full Disk Encryption and try the encryption task again.