Updating to Windows 10 may prompt you for a username/password when trying to connect the computers.
Turning the power off does not work, and turning off password protective sharing does not work.
The solution is:
- Sign in with the account you need to un-link.
- Click on the start button and type Manage your account
- Under Your Account find the option to un-link from whatever provider its linked to.
- You'll need to choose a new local user account name and password. Make sure the customer knows this information.
- Then you'll be signed out and asked to sign in again, with the new local account.
After logging back in, you should be able to connect to the server, as long as "file and printer sharing" is enabled and "password protected sharing" is turned off.