chntpw has no support for fully encrypted NTFS partitions (the only possible exceptions to this are encrypted partitions readable by Linux such as LUKS), usernames containing Unicode characters, or Active Directory passwords (with the exception of local users of systems that are members of an AD domain). The password changing feature is also prone to errors, so password blanking is highly recommended (in fact, for later versions of Windows it is the only possible option). Furthermore, the bootable image might have problems with controllers requiring 3rd party drivers. In such cases use of the stand-alone program in a full-featured Linux environment is recommended.[2]