After you make the registry change to set "NoLmHash" to 0, it is also important to change the password of the user account you are attempting to login as. By changing the password you ensure that the legacy lan manager password hash is generated and stored. The actual password doesn't have to change, you can use the same one, just make sure to go through the CTRL-ALT-DEL -> Change Password process. This made the difference for me, and I had a similar problem where a QNX system was trying to access windows file shares on Windows 7 & Vista with plain-text passwords. These are the steps I had to make to get it to work: Change the registry settings: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa "LmCompatibilityLevel"=dword:1 -allow older Lan manager style messages "NoLmHash"=dword:0 -store the older, less secure Lan Manager encrypted password Run "gpupdate /force" so these settings take effect. Change the password (to the same password) for the user(s) that need to connect.