Microsoft says a technical issue during a network capacity upgrade caused a global outage affecting Outlook, Teams, Copilot and other services for nearly 24 hours. Services were gradually recovering by Friday afternoon.
Microsoft said it is "deeply sorry" for the service outage to its products, including Outlook and Teams, which caused disruption around the world.
Services were broadly recovering by Friday afternoon, nearly 24 hours after issues first began, as Microsoft said it was making "encouraging progress" and email queues were nearing normal levels.
The outage hit more than 70 countries, disrupting business operations, government services and personal users. More than 430 million people use the affected products worldwide.
Users began reporting trouble accessing Microsoft 365 products on Thursday. Microsoft first acknowledged users in the Americas were unable to access Exchange Online mailboxes at 17:54 GMT on Thursday, and shortly after warned the disruption was possibly affecting Microsoft 365 globally.
Microsoft said the problem was a technical issue introduced during a "network capacity upgrade" and not related to cyber or artificial intelligence agents.
Institutions affected included the Japanese government, the Philippines Supreme Court, the Australian spy agency, and trains, hospitals and courts in North America. In the UK, parts of the NHS including GPs and hospitals were affected, as were some schools and police forces. NHS England said some staff were resorting to using paper records, while pharmacies warned of delays to prescriptions.
In Canada, the national rail network said passengers may not be able to receive email updates about their trips, and hospitals across the country also had issues with emails. In the US, staff members from the House of Representatives told Politico it had set back an entire day of legislative work as everything was on Microsoft's Outlook.
Singapore's government acknowledged some of its systems had been impacted, and in India, the outage disrupted work for many on Friday. In Turkey, advisers and officials attending the COP31 climate summit in Antalya were left frustrated by being unable to access Outlook.
Microsoft's services affected by the outage also included cloud-storage system OneDrive, AI assistant Copilot and certain cyber security tools.
Microsoft said it restored services gradually due to the scale of the problem and to help ensure services remained stable once they were up and running again.
"We are deeply sorry for the disruption this incident has caused our customers and partners," a Microsoft spokesperson said.
"We know the trust they place in our services and take that responsibility extremely seriously."
A full post-incident report will be released once Microsoft has completed a review.
Experts said the event was a "stark reminder" of how heavily businesses and vital services rely on a small group of big tech providers. Rob Demain, chief executive of cybersecurity firm e2e-assure, said the global Microsoft outage is a stark reminder of how heavily we rely on a handful of big tech providers. Matt Saunders, field chief technology officer at tech consultancy Adaptavist, said it would be challenging to mitigate against a similar problem and that organisations must have a plan in place for how to work without such tools.
Sources
This article was drafted with AI assistance and checked against the sources above. Company claims are reported as claims. Cover image is AI-generated.
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The Federal Aviation Administration lifted a nationwide ground stop caused by communications problems, allowing airplane departures to resume after roughly four hours.
Microsoft apologized for a widespread outage that disrupted Outlook, Teams and other Microsoft 365 services, saying it addressed the underlying issue and detected no malicious activity.
