/Type=ShadowType /For=ForVolumeSpec /Provider=ProviderNameOrID /AutoRetry=MaxRetryMinutes - Creates a new shadow copy of ...

%1 %2 /Type=ShadowType /For=ForVolumeSpec 
    [/Provider=ProviderNameOrID] [/AutoRetry=MaxRetryMinutes]
    - Creates a new shadow copy of the specified type for the ForVolumeSpec.  
    The default shadow copy Provider will be called unless ProviderNameOrID 
    is specified.  The ForVolumeSpec must be a local volume drive letter or
    mount point.  If MaxRetryMinutes is specified and there is another 
    process creating a shadow copy, vssadmin will continue to try to create 
    the shadow copy for MaxRetryMinutes minutes.
    - The provider ID can be obtained by using the List Providers command.
    When entering a Provider ID, it must be in the following format:
    where the X's are hexadecimal characters. 

    Example Usage:  vssadmin Create Shadow /Type=ClientAccessible /For=C:
    - Valid shadow copy types: