Unblock-​Tpm

Resets a TPM lockout.

Syntax

Unblock-Tpm
       -File <String>
       [<CommonParameters>]
Unblock-Tpm
       [[-OwnerAuthorization] <String>]
       [<CommonParameters>]

Description

The Unblock-Tpm cmdlet resets a Trusted Platform Module (TPM) lockout. TPM locks itself to prevent tampering or attack. This is called a lockout. To end a TPM lockout, you must provide a valid owner authorization value. You can enter an owner authorization value or specify a file that contains the value. If you do not provide a value, the cmdlet attempts to use a value stored in the registry.

For more information on TPM, see the Trusted Platform Module Technology Overview in the Technet library.

Examples

Example 1: Reset a lockout

PS C:\>Unblock-Tpm -OwnerAuthorization "vjnuW6rToM41os3xxEpjLdIW2gA="

This command resets a TPM lockout. The command specifies the owner authorization value vjnuW6rToM41os3xxEpjLdIW2gA=.

Required Parameters

-File

Specifies a file that contains the current owner authorization value for the TPM. You can use the TPM Management Console to create this file.

Type:String
Position:Named
Default value:None
Accept pipeline input:False
Accept wildcard characters:False

Optional Parameters

-OwnerAuthorization

Specifies the current owner authorization value for the TPM.

Type:String
Aliases:o
Position:1
Default value:None
Accept pipeline input:True (ByValue)
Accept wildcard characters:False

Outputs

TpmObject

This cmdlet returns a TpmObject object contains the following information:

  • TpmReady. Whether a TPM complies with Windows ServerĀ® 2012 standards.
  • TpmPresent. Whether there is a TMP on the current computer.
  • ManagedAuthLevel. The level at which the operating system manages the owner authorization. Possible values are Legacy, Balanced, and Full.
  • OwnerClearDisabled. Whether TPM can be reset. If this value is True, the TPM cannot be reset through the operating system by using the owner authorization value. If this value is False, the TPM can be reset through the operating system.
  • AutoProvisioning. Whether the computer can use auto-provisioning. Possible values are NotDefined, Enabled, Disabled, and DisabledForNextBoot.
  • LockedOut. Whether a TPM is locked out.
  • SelfTest. Information returned by a test that TPM runs.

Notes

  • Be sure to understand the protection logic TPM uses. The TPM allows at least one attempt to reset the TPM lockout by using the owner authorization value. For more information, see the Reset the TPM Lockout topic in the Technet library.