It's not my first time seeing that error, but its pretty rare.
I just shut down and unplugged my console the other day so I could move it while I cleaned. This was the 4th game I had played off my external since then, the other 3 didn't give me any errors, MCC is special.
The game did work after I tried to open it again, I played my first Halo match in over a year. Big team battle on a Halo 3 map, it lagged like hell the whole time but I was able to complete the match. Overall better than the last state I played the game in but still rough. (I have a wired 150mb connection and rarely get lag in other games)
343 was and still is 100% responsible for the state of MCC.. They were the main studio, it was their job to hold any other studios the game was contracted out to higher quality standards. There was no excuse for the broken state it launched in.