Windows logs in via samba on behalf of a domain it is not a member of. How to cure?

Question

Samba

Hello dear!
There is a computer No. 1, Windows 7, a standard workgroup WORKGROUP, the password request is disabled in the settings when accessing shared folders. The folder is shared and all computers on the network successfully get into it without any password requests, except for one ...
Computer No. 2, on the same subnet, Windows 7, standard WORKGROUP workgroup, however, when entering the first computer via samba, a request window appears login / password, and for some reason the domain "PC" is signed - this is the name of the computer itself No. 2. When entering the credentials WORKGROUP\user and the password from the first computer, it successfully gets into the shared folder.
How can I disable this credential prompt?

Answer 1

Maybe the username on computer #2 is different from user? Do the other clients share the same username?