The manual says press and hold the reset button for 10 seconds to reset the GF Home's settings:
"
Resetting GoFlex Home returns the device to its original factory settings. All the files stored
on GoFlex Home are retained—no files or folders are deleted—but all other settings, such as
user accounts and passwords, are removed.
"
Data on the disk is not cleared. Once you have set up your access you can then do as Jimmy says to format the drive if necessary.
