I found the terminal in the arbiter mission, held B and it brought me to the Halo Channel. Then it made a noise suggesting cant do this or no and booted me back to the game. I have unlocked the achievement though. Even when I go into the Halo Channel app it tells me I haven’t unlocked that terminal even though I have proof that I do. Please help!
I had this same problem but with the second terminal. I tried quitting the mission and restarting, this didn’t fix it either. The achievement didn’t unlock for me though. Any help 343?
I’m having the same problem, too! It goes to a black screen on the second terminal 
Then it buzzes and shoots me back to the pause screen.
Hope theyre working on a patch soon
Same problem. It eventually worked after I completed the mission and went into the halo separately. Bit of a hassle though.