Co-Op saves fail

New install. Solo game saves ok, co-op saves fail every time.

Tried Hard Reset of console, same issue. Not just on my xbox but my gf’s as well, exact same issue.

Any ideas on a fix?

Just thought I’d let ya know that you’re not alone. There are quite a few of us who have been reporting this issue across the various ways of communicating with 343i. No official response, and none of us have figured out a way to fix it. Super bummed as I just picked up the game 2 weeks ago to catch up on the saga with my Spartan Company. All we can do is keep reporting and gathering intel.