I have just finished beating halo on legendary and found all skuls and terminals. Now im trying to put in the codes for the terminals and its giving me this message “THIS DATA IS LOCKED. YOU MUST FIRST ACCESS TERMINAL 1 ON OR NEAR INSTALLATION 04.” Could anyone tell me how to unlock these terminals and get rid of this message??
Have you accessed Terminal 1? If yes,try clearing your Xbox’s local data for CEA and finding the terminals again, while connected to XBL.
The terminal videos are also available on YouTube.
If you did it offline, you’ll have to connect to Live so the server can read your data. Then enter the codes.
This issue has since been fixed. I suggest you attempt to re-unlock the terminals in the Classified section. 