I have a 360s 250Gb HDD.
At boot up my xbox goes through POST (xbox logo) then before it opens to dashboard I get a Update Required msg telling me to I need to install a system update from XBOX LIVE. When I go to start the update I get a error msg telling me I have no storage. So I cancel the update and dashboard opens up with me signed out of LIVE. When I go to storage settings it shows my 250Gb HDD as unformatted. ?? Weird.