When attempting to remote logon via Remote Desktop connection to a remote computer with OS Windows XP or Windows Vista computer, the log on may be rejected error messages.
• Your credentials did not work.
• Unable to log you on because of an account restriction.
• An authentication error has occurred.
The Local Security Authority cannot be contacted
Remote computer : ZZZZZ
By default, Windows XP and Windows Vista does not allow nor permit user account without password set or user name with blank (null) password to connect and log in remotely via Remote Desktop Protocol (RDP).
For security reasons this restriction is set windows XP and Windows Vista
The following workaround allow user to login remotely via Remote Desktop Connection (RDP) client to Windows XP and Windows Vista PC allows to create and set a password for the user account that requires to logon remotely
Enable Remote Login via Blank Passwords by using Local Security Policy
The configuration to enable null (blank) passwords logon must be done on the host computer, that needs be remotely logon.
Go , Control Panel -> Administrative Tools (Under System and Maintenance in Windows Vista) -> Local Security Policy. Alternatively, run GPEdit.msc (Group Policy Editor).
Expand Security Policies -> Local Securities -> Security Options (for user using Group Policy Editor or GPEdit.msc, expand Local Computer Policy -> Computer Configuration -> Windows Settings -> Security Settings -> Local Policies -> Security Options). Locate Accounts: Limit local account use of blank passwords to console logon only policy, and set its value to Disabled
How to Configure Blank Passwords Allowed for Remote Log On via Registry
Windows XP and Windows Vista stores the value of the policy set above in a registry key named “LimitBlankPasswordUse”. To unlock the limitation of cannot establish Remote Desktop logon with user account without a password, simply set the value data for LimitBlankPasswordUse to 0. Alternatively, copy and paste the following text to a text file, and save with a .reg extension. Then run the .reg file to merge the value to registry.
Windows Registry Editor Version 5.00