If you use Windows10 and some SMB shares (maybe on Debian), you maybe run into the problem that Windows10 ask you for a username and password when you connect to the SMB shares, though it was never needed before.
This is because you are newly connected with an offical Microsoft account. Further before, you use a local account and this problem does not appear.
The solution:
Just login with somthing as username and password.
RobTranquillo 