For the past four days I have been getting this same message when I try to access my xbox live account:
"A system update is required to sign in to LIVE, but the update is unavailable. If problem persists vist xbox.com/support"
I have tried waiting and retrying it, and updating my info in the security stuff and clearing the cache. However the same message appears everytime I try to go on live.
Any help would be appreciated.