Microsoft 365 outage stretches past 12 hours, disrupting Outlook, Teams and governments worldwide

What happened

A global Microsoft 365 outage that began on Thursday remained unresolved more than 12 hours later, leaving millions of users without access to Outlook email, Teams meetings and other core productivity tools.

According to CNN, outage reports tracked by Downdetector reached 74 countries and territories within roughly an hour of the first signs of trouble. Microsoft first acknowledged problems with its email services on Thursday, and by early Friday the disruption was still widespread as Europe came online.

The affected user base is enormous. Figures on Microsoft's own website, cited by CNN, put Microsoft 365 app usage at more than 430 million people, with over 90% of Fortune 500 companies using its Copilot AI chatbot.

Microsoft's response so far

In updates posted to its Service Health Status page early Friday, Microsoft said it was reviewing server performance and verifying that developed patches had been applied and were working as intended after infrastructure reboots. "At this point, we have observed marginal success," the company wrote.

About 30 minutes later, Microsoft reported "positive results for service stability and increased capacity" following its latest traffic optimization actions, according to CNN.

A separate update from Microsoft's 365 Status account on X, however, said changes applied to improve serviceability were "not taking as expected," and that the company was identifying alternate workstreams to increase capacity "in the face of sustained traffic management imbalances." The incident is tracked under the IDs EX1550543 and MO1550821 in the Microsoft 365 admin center.

A Microsoft executive confirmed the outage was not the result of a cybersecurity breach, and the company reiterated it was not aware of any malicious activity. Microsoft has promised a post-incident report covering the root cause and repair work once services are fully restored.

Banks, courts and airlines affected

The outage reached far beyond office workers. According to CNN's reporting:

• City governments across the United States, including Miami Beach, Austin and Jacksonville, reported inbound and outbound email disruptions and asked residents to phone local offices and agencies where necessary.
• Some Japanese government services switched to paper documents, courts in the Philippines faced delays, and Australian schools, courts and government services were also affected.
• In Hong Kong, staff at Morgan Stanley and Goldman Sachs told CNN their work had been disrupted through to the lunch break.
• Airlines including IndiGo, Akasa Air, CemAir and Air India reported disruption to their email support and communications. None of the carriers reported flight disruptions.
• At least one American company postponed its quarterly earnings call.
• Banks warned customers to watch for scams and phishing attempts exploiting the outage.

Why it matters

The incident is a live demonstration of how much administrative and commercial infrastructure now depends on a single vendor's cloud. Email, meetings, government paperwork and court proceedings stalled because one provider's traffic and capacity management failed, and Microsoft's own updates show the remediation is not straightforward: reboots, patches and traffic rebalancing have produced what the company itself described as only marginal success.

The timing also matters. CNN notes that the outage lands in the middle of Europe's push for tech sovereignty, with France's prime minister having said earlier this year that officials would drop US-owned video conferencing tools to reduce dependence on non-European providers. Commentators interviewed by CNN suggested the outage would sharpen that debate and serve as a wake-up call about the vulnerability of cloud convenience.

For IT teams everywhere, the practical lesson is the one every major cloud outage teaches: fallback channels that share the same provider are not fallbacks at all, and Microsoft's promised post-incident report will be required reading for anyone running critical workloads on its platform.