Linux Mint is a spin-off distribution of Ubuntu Linux, and as such shares many characteristics of its more prominent cousin. One such trait shared by the two Linux versions is the disabling of the root account by default. Rather than enabling the root access and possibly leaving the system open for attack by hackers, the Mint Linux developers disabled the account. Nevertheless, if you do want to enable the root account in Mint, you can do so by setting a password for it.
Open a terminal by clicking the "Menu" button at the lower left corner of the Linux Mint desktop and selecting the "Terminal" application shortcut in the menu.
Type "sudo passwd root" into the terminal and press "Enter."
Type your current account's password at the password prompt and press "Enter" to authenticate with the sudo command.
Set a password for the root account by typing it at the prompt, pressing "Enter," retyping it to confirm and pressing "Enter."
Type "su" at the terminal and press "Enter" to become the root user. You can also log in as root by specifying "root" at a login prompt.
Mint's developers recommend against logging into your graphical desktop as root. Logging in as root allows applications access to your entire system. Attackers can exploit security vulnerabilities in any application to compromise your entire system if you log in as root.