I used LMDE 201204 with default settings. Hence, the root account is passwordless.
synaptic is launched from the "Menu". An administrative password is asked to gain root privilage to manage packages. My password is accepted as the administrative password.
Somehow, I set a password for the root, the required password became the root's password. I want to revert it back to my own password, so I edit /etc/shadow to clear the password field of the root. No matter the field is omitted (not any byte, flanked by colons) or filled in with a single '*', my password failed to be accepted as the administrative password to launch synaptic.
Thank you in advance.