Microsoft 365 services resume following 24-hour outage

Microsoft 365 services have largely returned to operation after a major outage affected businesses, governments, and tens of millions of users globally, according to the company’s status page. The disruption originated on the East Coast around lunchtime on Thursday, with users reporting Outlook issues to Downdetector shortly after 12 pm ET.

Within an hour, Microsoft confirmed it was looking into reports of an outage that initially affected only North America. The problem quickly escalated, impacting more than 70 countries across the globe.

The exact reason for this unprecedented failure is still not fully understood, though Microsoft has consistently denied that a cyberattack was responsible. The company also stated that AI or AI agents played no part in the incident.

“We are seeing broad recovery and stability across our services,” a Microsoft spokesperson said in a statement. “This was a technical issue not related to cyber or AI/agents. The incident was introduced by an issue during an earlier network capacity upgrade that surfaced following a recent network change. We have addressed the underlying issue and continue to restore service to remaining customers and regions.”

The organisation has pledged to release a “full post-incident report” once a complete review of the failure is finished. As platforms like Outlook, Teams, and Copilot resume normal functions, users may experience significant inbox clutter.

“You're probably going to get a lot of notifications when things come back,” remarked independent researcher Jonathan Leitschuh. Microsoft noted that it had extended the email queue time to 48 hours to ensure all messages sent during the downtime are eventually delivered.

Leitschuh noted that even as systems recover, users should expect “a flood of notifications a few hours down the pike” as various subsystems become fully operational again. The overall impact of the event is significant, though it may never be entirely quantified.

Governments in nations from Japan to the United States experienced widespread operational disruptions. Airlines faced difficulties communicating with passengers, while numerous emergency services and law enforcement agencies were forced to stop their work. Additionally, hospitals reported substantial interruptions to their daily operations.

The incident highlights the dangers of global reliance on a single provider for essential infrastructure. “We're very interdependent on these systems in modern life,” Leitschuh said. The events suggest that in future disruptions, delayed emails could be the least of the concerns.