As he used to on Windows he installed Manjaro with a user without password.
Later to login he just clicked on “Login” button.
But after the default 5 mins without activity KDE locks the screen and he asked me how to unlock. I supposed that he just needed to click “Unlock” button but that does not work.
To double check I reinstalled this .ISO on a test notebook (with my user without password) and verified that really I cannot unlock screen just clicking “Unlock” (as opposed to login where click “Login” works).
The only way I found to “escape” was hit CTRL-ALT-F2, login with my username (without password) and “sudo reboot” or “sudo poweroff”.
He argued with me “if I can’t unlock without password why even allow create a user without password?”.
Indeed, there is some illogical things. I tested some, my results:
On existing installation on VB from same .iso as your but with kde-unstable. I can’t create user without password from GUI (it’s also impossible on stable version), but when I removed password through console I can’t confirm your observations. I was able unlock screen both with Unlock button and with Enter key.
I’ll try create user without password during installation and see what it change. And try stable KDE – maybe there is issue
EDIT: When I created user without password during installation I observe the same things as you. But again, when I created test user after this installation I was able to unlock screen without problem as I described before. So this is Manjaro issue, not KDE issue. @Manjaro-Team there is issue with installer.
EDIT2: @peracchi probably I found workaround. Try sudo passwd -d USER on user created without password during installation – it worked on me.