Fix FVE_E_AD_INVALID_DATATYPE (0x8031000B) on BitLocker

You get error FVE_E_AD_INVALID_DATATYPE (0x8031000B) when BitLocker tries to back up its recovery key to Active Directory but finds the data type doesn't match what it expects. I've seen this most often in hybrid environments where the AD schema got mangled during a domain upgrade, or when someone copied recovery keys manually into the wrong attribute.

Had a client last month — manufacturing company with 200 workstations — after they migrated from Server 2008 R2 to Server 2019, every new BitLocker encryption failed with this code. Took me three hours to trace it back to a schema attribute that hadn't been updated. Don't waste time like I did. Here's the fix order.

Cause 1: Attribute type mismatch in AD (most common)

BitLocker stores recovery keys in the msFVE-RecoveryPassword attribute on a computer object. This attribute needs to be of type Unicode String. If it somehow got changed to Integer or Octet String (usually through bad schema extensions or manual ADSI edits), BitLocker chokes with 0x8031000B.

Check this with ADSI Edit:

1. Open ADSI Edit (run adsiedit.msc).
2. Connect to the Default Naming Context.
3. Right-click the affected computer object, choose Properties.
4. Find msFVE-RecoveryPassword in the Attribute Editor.
5. If the value shows anything other than a 48-character recovery key (like 128-char hex or a number), the type is wrong.
6. If you can't see the attribute at all, it's not populated — different problem.

The fix: you can't change the attribute type back through ADSI Edit on a live domain. You need to either:

• Delete the bad attribute value from the computer object, then force BitLocker to re-back up the key.
• Or, if the schema attribute definition itself is corrupted, you'll need to extend or re-extend the schema using adprep /forestprep from Server 2016/2019. But that's risky and requires forest-wide admin.

Quick fix for the attribute on a single machine: use PowerShell to remove the bad value:

$comp = Get-ADComputer -Identity "COMPUTERNAME" -Properties msFVE-RecoveryPassword
Set-ADComputer -Identity $comp.DistinguishedName -Remove @{msFVE-RecoveryPassword=$comp.'msFVE-RecoveryPassword'}

Then on the affected machine, run manage-bde -protectors -adbackup C: to push the key again.

Cause 2: Schema version mismatch after domain upgrade

This one bit me hard. If you upgraded your domain controllers from Server 2008 or 2012 to Server 2016/2019/2022, the schema version for BitLocker might not have updated. The msFVE schema class relies on specific objectVersion numbers. If your schema version is lower than 87 (for Server 2016), the attribute type mapping gets confused.

Check your schema version:

Get-ADObject "CN=Schema,CN=Configuration,DC=yourdomain,DC=com" -Properties objectVersion | Select-Object objectVersion

You need version 87 (Win2016) or higher. If it's lower, run adprep /forestprep from the new domain controller media. Yes, you'll need schema admin rights. Don't skip this — I've seen BitLocker fail on every new machine in a domain running schema version 69 (Server 2008).

After updating schema, reboot the domain controller that processes BitLocker requests, then re-run the backup on the client.

Cause 3: Group Policy forcing wrong backup behavior

Sometimes the error isn't the data itself — it's how BitLocker tries to store it. Group Policy can dictate that recovery keys go to AD in a specific format. If the policy says "store as recovery password only" but the client tries to store the key protector (a different data type), you get 0x8031000B.

Check these GPO settings under Computer Configuration > Administrative Templates > Windows Components > BitLocker Drive Encryption:

• Store BitLocker recovery information in Active Directory — set to Enabled
• Choose how BitLocker-protected drives can be recovered — set to "Allow recovery password" and "Allow recovery key"

If the policy is set to "Require" for both values, that's fine. But if it's set to "Do not allow" for either, you'll get the error. I've seen admins set "Do not allow" thinking it's secure, but it breaks the backup entirely.

Fix: update the GPO, run gpupdate /force on the client, then re-try the backup.

Quick-reference summary table

Bottom line: this error is almost always a schema or attribute issue. Don't re-image machines or reset TPM unless you've checked AD first. The fix is usually a quick PowerShell one-liner or a schema update — not a full rebuild.