Buffalo TS-XL User Manual page 54

Initialization
You can restore all settings to their factory
defaults by clicking Restore TeraStation. You
can choose to either keep the current admin
password after initialization, or revert the
password to its default setting of "password".
You can also initialize your TeraStation from
the Init button, located on the bottom side of
the display panel (open the door to access it),
Init Button
or the front of the rackmount TS-RXL (remove
the cover to access it). Holding down the Init
button for 3 seconds will initialize all settings
including the admin password.