I have been decrypting BitLocker on my USB disc drive for the past two days, and I recently noticed that it had been at "82.1% Completed" for hours. Task manager now shows 0% disc activity for the drive, whereas before it was 100% (for the past two days).
Drive: 4TB (USB HDD drive) Bitlocker (full) encrypted, auto-unlock
enabled. Recovery key working.
Main usage: Backups
Unique information on the drive: 1TB of data not backed up anywhere
else
Windows version: 10 Pro 64-bit 1909
Bitlocker version: 2.0
USB port: 3.0
What I have tried:
1a. Pausing and resuming BitLocker
1b. Rebooting the machine and trying again
1c. Booting into safe mode and trying again
1d. Booting into recovery mode (X:\ administrator command prompt) and using "manage-bde"
1e. Disabling Secure Boot in the BIOS and trying again
1f. Enabling CSM in the BIOS and trying again
1e. Using "manage-bde" to pause, resume, start encrypting and then start decrypting again (on steps 1b, 1c, and 1d).
1f. Connecting the drive to another Windows 10 Pro 64-bit computer and trying steps 1a and 1e.
1g. Running "chkdsk" in an administrator command prompt, and via the GUI version in drive properties, both said no errors were found.
1h. Attempting to use "repair-bde F: G: -rp [Full recovery password, that has been tested and is working] -Force", however I don't have another drive that is 4TB capacity (the "G" drive is a 32GB USB stick). Output:
Bitlocker Drive Encryption: Repair Tool version 10.0.18362
Copyright (C) 2013 Microsoft Corporation. All rights reserved.
LOG ERROR: 0xc000003d
Needs at least 3815318 MB of free space for repair.
ERROR: Not enough free space on output volume to perform repair.
What I have observed:
30-60% disc activity on the drive for about a second on steps 1a, 1b, 1c,
100% disc activity on the drive when using "manage-bde -on F:" (re-encrypting the drive)
100% disc activity on the drive when using "manage-bde -off F:" (decrypting the drive again) AFTER step 2, but only until (I assume) BitLocker gets to the same place where it was stuck before, as disc activity drops to 0%. This leads me to believe that BitLocker may be getting stuck in a particular place or on a particular file.
I still have full access to the drive and can read/write perfectly fine. Have successfully viewed files, added files and removed files (for testing). I can read/write perfectly fine on both Windows machines I tested on.
TLDR: Bitlocker decryption of a 4TB USB HDD stuck at 82.1% with 0% disc activity for hours. No errors found on the drive, files still fully accessible.
I have already contacted an "IT Pro/Admin" from Microsoft Support who guided me with steps 1e and 1f, but BitLocker still appears to not be doing a lot.
I have also looked at the BitLocker event logs, but nothing about errors is displayed, simply status messages such as "BitLocker decryption was started for volume F:." and "The BitLocker protected volume F: was unlocked. Protector GUID: {xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx} Identification GUID: {xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}"
If you have any ideas or suggestions for fully decrypting the drive, please let me know.
