Microsoft 365 outage drags on for nearly 10 hours during bad night for North American infra

Down to 364.5 already: Redmond's crappy 2026 continues

Microsoft 365 suffered a widespread outage last night affecting multiple services including Outlook – adding to the megacorp's troubled start to 2026.

The software and cloud biz acknowledged problems at 1937 UTC, when many users found Microsoft 365 services suddenly unavailable or sluggish. In addition to Outlook, Defender and Purview were also downed.

Microsoft blamed "a portion of service infrastructure in North America that is not processing traffic as expected."

Affected users reported internal mail flowing slowly, while external email had packed up altogether. One wailed: "You got to be kidding me! We haven't gotten emails since 1:30 pm and we run a financial company with clients!!"

At the peak of the outage, 15,000 reports flooded incident-tracking site Downdetector.

Recovery was painfully slow as Microsoft worked to restore the infrastructure and balance traffic as the environment lurched back into life. By 0533 UTC, almost ten hours after the company first admitted there was a problem, Microsoft reported: "We've restored access to the affected services and mail flow remains stable."

Just under an hour later, it claimed: "We've confirmed that impact has been resolved."

Some users disagreed, with one posting: "No it has not been resolved," and another writing: "Our tenant is still unable to receive external email. I do not think this is resolved." Judging by the slowdown in complaints, services seemed back up and running for many.

The Register asked Microsoft for more details regarding the cause of the outage and the steps taken to ensure it won't happen again. We will update this piece should the company respond.

In the meantime, service has been restored as far as Microsoft is concerned, although we've no doubt that somewhere in Redmond an engineer is removing the "5" from Microsoft 365 and replacing it with a "4.5." ®