Bitlocker de-encrypt failed

Question

I have an old Windows 10 laptop that I hadn't used for a while. When I powered it up around the end of July 2024 for the first time in a year, a Windows update was installed automatically which caused the hard drive to be Bitlocker encrypted, which meant that I had to put the 48 character key in every time I wanted to use it, which is not only tedious but extremely annoying. The Bitlocker on the hard disk had never been used before,

After looking for fixes to this after any August updates, I realised that I could turn off the Bitlocker encryption by logging in as Admin and disabling it. It started to un-encrypt the disk so I left it running, ony to come back to find that the disk now seems to be corrupted and the computer unuseable. Sometimes, it will load into Windows but then locks up when I try to do anything with it. Other times, it comes up with an error and doesn't even get as far as loading Windows.

Is there anything I can do to recover the disk? I can't re-format it as I don't have any installation disks (there isn't even a disk drive!) so I'm pretty-much stuffed. I have taken the disk out and connected it to a computer via USB using a caddy and it is accessible with no need to enter the encryption key, but Computer Management reckons it is still encrypted.

*** Moved from Windows / Windows 10 / Windows update, recovery, and backup ***

Answer 1

Hello aseame,

thank you for posting on the Microsoft Community Forums.

Since you mentioned you can access the disk via USB caddy on another computer, we have a few options to work with:

1. Check Disk Utility (chkdsk):
   • Connect the disk to another computer using the USB caddy.
   • Open Command Prompt as an administrator.
   • Run the command:
   chkdsk /f X:

Replacing X: with the drive letter of the connected disk. This will check the disk for errors and attempt to fix them.

2. If you can access the disk, prioritize copying important files to another storage device to ensure you don't lose any critical data.
3. BitLocker Decryption via Command Line:
   • Open Command Prompt as an administrator on the host computer.
   • Use the following command to continue the decryption process:
   manage-bde -off X:

Replacing X: with the appropriate drive letter.

4. If you don’t have an installation disk, you can create a Windows 10 recovery USB on another working computer. You will need a USB drive with at least 8GB of storage. More details please visit Download Windows 10 (microsoft.com). then boot your old laptop from the recovery USB and attempt a system repair or use the Command Prompt from the recovery environment to run chkdsk and other diagnostic tools.
5. If the above steps do not resolve the issue, you might need to reinstall Windows. Use the recovery USB created in the previous step: Boot from the USB and follow the instructions to reinstall Windows. During this process, you may have the option to keep your personal files, though this is not guaranteed.

These steps should give you a good starting point for recovering your disk or, at the very least, saving your important data.

Best regards,

Lei