In Macintosh operating system based computers, 'root' or the 'super user' account is a special account meant to be used by the system administrator. This account has the highest privileges among all the user accounts and is entitled only to some authorized individuals in the organization to avoid misuse, abuse or any other undesired activity. As Mac OS X is a multi user operating system, the root account also allows the administer to create and manage other user accounts according to the requirements. Moreover, the root or the super user account is responsible for the running of various system processes in a Macintosh system. Hence, due to any reason, if the root account is deleted, the system may not boot properly or even at times, completely fail to boot. Under such a situation of data loss or inaccessibility, with advanced Mac recovery techniques, all your valuable data can still be recovered.

In normal usage, it is always advised to keep the root user account disabled in the system, in order to avoid any accidental or intentional manipulation. Even, in many advanced computer systems, including that of the Macintosh operating system based computers, Apple has by default disabled the root account. However, along with this, it is suggested, never to delete the root account irrespective of the fact that it has been kept disabled. Because, there are many system processes, which need a root account validation to run, even if the account does not contain any password to run or being disabled. Therefore, if due to any reason, the the super user account gets deleted, you fall under a great problem of data inaccessibility.

Resolution:

In the above case, you need to perform a fresh installation of the Mac OS X. The process must be performed with extreme care, as your valuable data is associated with it. The following steps may guide through the process:

Boot from the Mac OS X installation disk to reinstall the operating system.

Press the key 'C' or the 'Option' to select the CD/DVD as the boot device at the startup. When, asked, provide the 'Open Firmware' password.

Select the 'Archive and install' option for the installation process and also select the option 'Preserve user and network settings'.

Reboot again and pressing the key 'C' or 'Option', change the boot device to hard disk.

Lastly, move files from the location /Previous Systems/Previous System1/Library to the location /Library.

If you commit any mistake during the above process or the problem still persists, you need to perform a fresh installation with the 'Erase and Install' option. If you have mistakenly chosen the 'Erase and Install' option, then you have to restore the data from the valid backup. In case, you failed to restore the data from the backup, the only option left is to opt for an advanced Mac data recovery software to get back the formatted data.