Editing Security Account Manager (section)

===Removing LM hash===
LM hash is a compromised protocol and has been replaced by NTLM hash. Most versions of Windows can be configured to disable the creation and storage of valid LM hashes when the user changes their password. Windows Vista and later versions of Windows disable LM hash by default. Note: enabling this setting does not immediately clear the LM hash values from the SAM, but rather enables an additional check during password change operations that will instead store a "dummy" value in the location in the SAM database where the LM hash is otherwise stored. (This dummy value has no relationship to the user's password - it is the same value used for all user accounts.)