I have a customer who has a Windows 7 server and windows 7 clients attached to it. Not using a Homegroup option. We just shared the folders and mapped the drive. And everything has been working fine for several years now.
Now they add a Windows 8.1 computer and with a new user name and password added and we can not setup a mapped drive. All the computers can see each other and the are on the same network name WORK.
The new user name is the same on the server as it is on the Windows 8.1 computer.