I've tried this with no luck:
1.Boot into single user mode (press Command-S at power on)
2.Type fsck -fy
3.Type mount -uw /
4.Type launchctl load /System/Library/LaunchDaemons/com.apple.DirectoryServices.plist
5.Type dscl . -passwd /Users/username password, replacing username with the targeted user and password with the desired password.
After running step 5 I get this error:
<dscl_cmd> DS Error: -14009 (eDSUnknownNodeName)
I have a user account that doesn't show when using the password reset tool. I tried this method and it doesn't work either. I can see the users folder under /Users but can't seem to reset the password.