Do Not Require Login to Access Shared Folders
If you share folders on your Windows PCs, you can require remote users on the network to login in order to access them. If you don’t want remote users to be required to login, you can also disable this functionality:
Open the Run dialog or a Command Prompt, and then enter the following and hit Enter: control userpasswords2
On the dialog box that appears, uncheck the Users must enter a user name and password to use this computer check box, and then click OK.