Resetting Lost Root Password - gorect/Proxmox GitHub Wiki

Hold down shift the access the grub boot options. Select E while over the Proxmox Option to change the boot options for that. Go to the line that starts with linux and ends with the quite flag and add "init=/bin/sh" (without quotes) And hit F10 to boot into the environment with out having to know the root password.

Now if you wish to reset the root password you will need to mount the root directory as read writable. mount -rw -o remount / Then simply use the normal passwd command to reset the root password and reboot.