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veracrypt / VeraCrypt

Disk encryption with strong security based on TrueCrypt
https://www.veracrypt.fr
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Windows 10 failed update caused unmountable partition #742

Open ghost opened 3 years ago

ghost commented 3 years ago

Expected behavior

On booting to VeraCrypt and entering the password and PIM, I expect to see the messages "authorizing...", "success" and "start len ", and then boot into Windows 10 (which is on an encrypted partition).

Observed behavior

Upon correctly entering my password and PIM, I get the messages "authorizing...", "success" and then "start len ". However, instead of booting into Windows it once again asks for password, then PIM, and then continues to loop if both are entered correctly. Attempting to mount the partition using the cli tool for Ubuntu also fails with the error message shown in the 1st image of the Screenshots section. I am, however, able to mount another partition which is encrypted with the exact same password and PIM with no errors (2nd screenshot). Yesterday I had a Windows update which failed and rolled back automatically. After that I was successfully able to boot into Windows once, and then did not use Windows until today when I was met with the password loop. I suspect this is the root of the issues I am experiencing, but I (oddly) cannot even boot into Windows by pointing to /EFI/Microsoft/Boot/bootmgr.efi which instead takes me to the Veracrypt password and PIM entry screen.

Steps to reproduce

  1. Have a Windows 10 update fail to install and automatically rollback
  2. Turn on machine and attempt to mount partition
  3. Correctly enter password and PIM
  4. Repeat 3.

Screenshots

image image

Your Environment

VeraCrypt version: 1.24-Update7

Operating system and version: on encrypted partition: Windows 10 20H2. Also tested with: Ubuntu 20.10

System type: 64-bit

ghost commented 3 years ago

I can confirm your observed behaviour on my system. Although in my case I don't think it was triggered by a failed update. I simply started the update on Windows 10 20H2 and chose "Shutdown and install updates". After shutting down Windows my machine turned on again and the Veracrypt loader freezes at the exact position you described. I'm also unable to mount the partition with another operating system.

Edit: Restoring the partition with the Rescue Disk works.

idrassi commented 3 years ago

Using the Rescue Disk will fix such issue which is caused by Windows Update process deleting the file "EFI\Microsoft\Boot\Bootmgfw_ms.vc" needed by VeraCrypt. It would be helpful for those having this issue to check the content of the EFI system partition and list the content of the "EFI\Boot" and "EFI\Microsoft\Boot" folders (for example by booting on Linux).

Concerning mounting the system partition on another operating system, one must remember to specify the option to mount as system encrypted partition. On linux CLI, this is done by specifying "--mount-options=system" and in UI this is done by clicking on "Options" button on password dialog and checking the option "Mount partition using system encryption". Also, one must ensure to type the password for system partition using US keyboard layout since this is the only layout supported by BIOS boot.