Microsoft 365 services are coming back online after an outage disrupted users around the world, including businesses and governments. Microsoft says recovery is broad, though some customers and regions are still being restored.
A service disruption spread worldwide
Reports of Outlook problems began around lunchtime on the East Coast on Thursday. Users flagged issues to Downdetector just after 12 pm ET, and within an hour Microsoft said it was investigating an outage that was then limited to North America.
The disruption soon affected more than 70 countries. Microsoft 365 services including Outlook, Teams, and Copilot were among those returning as the company worked to restore service.
Microsoft has said the outage was not caused by a cyberattack. It also ruled out AI or AI agents as a factor. The company described the incident as a technical problem connected to an earlier network capacity upgrade, which became visible after a recent network change.
Recovery may bring delayed messages and alerts
Even when services become available again, users may not see an immediate return to normal. Messages and notifications that accumulated during the disruption can arrive later, creating a second wave of activity in inboxes and other systems.
Microsoft said it increased the email queue time to 48 hours so messages people tried to send during the outage would have more time to be delivered. Independent researcher Jonathan Leitschuh warned that users could still see many notifications as related systems come back online.
“You're probably going to get a lot of notifications when things come back,” says Jonathan Leitschuh, an independent researcher.
Leitschuh also said a surge of alerts could follow hours after the main recovery, as subsystems return. That means a service appearing restored does not necessarily mean every delayed message or notification has already arrived.
Organizations felt the disruption in different ways
The complete impact may not be known. Governments from Japan to the United States reported disruption to a range of functions, while airlines described problems communicating with customers.
Law enforcement and emergency services were among the organizations whose work ground to a halt. Hospitals also reported widespread interruptions to their operations. The reports show how a cloud service outage can reach beyond email and affect services people depend on for essential work.
Microsoft promises a post-incident report
Microsoft says it has addressed the underlying issue and is continuing to restore service for remaining customers and regions. The company has promised a “full post-incident report” after reviewing what went wrong.
Until that review is complete, the precise cause and full extent of the incident remain unclear. The explanation so far ties the problem to network capacity work and a subsequent network change, but Microsoft has not yet provided its promised full account.
The outage also highlighted the reliance of businesses, public services, and individuals on shared cloud platforms. As Leitschuh put it, “We're very interdependent on these systems in modern life.” Recovery can restore access, but the disruption shows how widely a problem with one provider can be felt.