Microsoft restores global Microsoft 365 services after multi-day outage

Microsoft announced on Saturday that it had restored Microsoft 365 services for all remaining customers and regions after a multi-day outage that began on Thursday. The company said the issue was resolved following a network-capacity upgrade that had introduced a fault, and it directed users to the incident reference MO1550821 for further details.

The disruption affected a range of public and private organisations, including government agencies in Japan, Singapore, Australia, the Netherlands, Belgium and France, as well as courts, healthcare providers, airlines, banks and schools. In the United Kingdom, NHS England and several courts reported operational difficulties, while staff at the House of Representatives in the United States said they lost a day of work.

Australian federal police and the national security agency ASIO confirmed partial impacts on their systems. In Japan, government email services were unavailable, prompting staff to use text messaging. Indian airlines IndiGo and Akasa Air reported issues with email support, and Taiwanese financial firms experienced interruptions to fund-management services.

Microsoft said the outage affected Outlook, Teams and the Copilot AI assistant, and Downdetector logged reports from users in more than 70 countries and territories. The company, which serves roughly 430 million users of its 365 apps, clarified that the incident was not related to cyber-attacks or AI agents.

Experts noted that large-scale outages often result from complex interactions between well-understood systems. Security-engineering professor Steven Murdoch said such events highlight the inherent risk of failure in intricate digital infrastructures, while Tim Clement-Jones described the incident as an illustration of the UK's reliance on U.S. technology providers.