Xbox’s Chief Technology Officer, Scott Van Vliet, has offered transparency and an explanation for the system and service outage that affected game libraries, sign-in, and game launching for many players from late Sunday night and well into Monday, vowing to “do better.”

In a post on X, Van Vliet attributed the issue to a failure of “a licensing service that sits outside of Xbox, but which Xbox depends upon.” He did not name the service, but said it was “an internal service at Microsoft that is shared across multiple products, not some random system.” He continued: “This caused some sign-in scenarios to fail, and it caused many scenarios that require an entitlement check to also fail, such as listing out your Full Library and launching games that you own,” he continued. “It also affected several of our publishing and store partners who depend on those same systems which is why some of you saw issues in specific games and not others.” He called it “an unacceptable situation” and that Xbox “must do better to support you.”

To address the problem, the Xbox CTO said, “Our on-call teams caught the first signals overnight through automated monitoring and declared a major incident. Once we isolated the failing infrastructure, we shifted traffic onto the healthy parts of the system while the team continued to work towards a root cause. Service came back unevenly across regions which is why some of you recovered hours before others.”

Van Vliet said that for the company’s next step, “We’re running a full post-incident review. I care less about the one-line root cause and more about the real questions: why a failure in one service was able to take down this much, why recovery took as long as it did, and what we change so a single point of failure can’t ruin your night again. That means hardening the dependencies underneath sign in and game launch, improving how we detect and contain this class of failure, and being faster and clearer with you when something breaks.”

He concluded by thanking Xbox gamers for their patience, and said, “We’ll do better.”

This incident follows PlayStation suffering its own prolonged system and service outage, while Xbox prepares for this week’s wide launch of Halo: Campaign Evolved, the Unreal Engine 5-based remake and 25th anniversary celebration of the original Xbox’s killer app. IGN gave Campaign Evolved a 7 out of 10 in our review.

Ryan McCaffrey is IGN’s executive editor of previews and host of both IGN’s weekly Xbox show, Podcast Unlocked, as well as our semi-retired interview show, IGN Unfiltered. He’s a North Jersey guy, so it’s “Taylor ham,” not “pork roll.” Debate it with him on Twitter at @DMC_Ryan.