[*]Logon to the computer with administrator account.
[*]Click on Start button.
[*]At bottom of start menu in search box type gpedit.msc command and press enter key.
[*]On Local Group Policy Editor snap-in under Computer Configuration expand Windows Settings and then expand Security Settings.
[*]Expand Local Policies and click on Security Options.
[*]From the right pane double click on Accounts: Limit local account use blank passwords to console logon only and from the opened box select Disabled radio button.
[*]
Allow Blank Passwords
[*]Once done, click on Ok button and close Local Group Policy Editor snap-in.
[*]Open Command Prompt and in command window type gpupdate /force to update here computer policy with latest configuration.
[*]Close Command Prompt.