I've this strange issue occurring after I upgraded the os from 16 to 18.
At first, it wouldn't let me in, saying that the password is incorrect even though it was right. So I rebooted with recovering mode on, entered into root, and changed my user's password with a new one.
Rebooted, logged in, all perfect. But the moment I lock my screen, it wouldn't take me back, stating that the password is incorrect. I don't want to reboot every time I want to log in. AND, most importantly, sudo password for this user is also incorrect. Sudo password does not match with the login password for this user, apparently. STRANGE.
It's frustrating, but I have no idea what has to be done?