Tokyo: A major disruption to Microsoft's online services affected users across dozens of countries on Thursday and continued into Friday, disrupting email, workplace applications and some government operations. Microsoft was still working to restore services after several recovery attempts failed to deliver the expected results. The outage affected Microsoft 365, Outlook and Microsoft Teams, along with several other services connected to Microsoft's cloud infrastructure. Reports of problems came from 74 countries and territories, highlighting the international reach of the disruption.
Japan also confirmed that its government IT infrastructure had been affected. The incident raised concerns about the dependence of businesses and public institutions on cloud services for their daily operations. Downdetector, an online platform that tracks service disruption reports, recorded a peak of 138,058 reports of Outlook problems in the United States. Thousands of additional reports concerned Microsoft 365 and Teams. These figures represent user reports rather than the confirmed number of customers affected.
The problems were initially reported mainly in the United States before reports emerged from other regions, including parts of Asia and the Asia Pacific. Users experienced difficulties accessing email accounts and workplace applications. Microsoft confirmed that the disruption affected Exchange Online, the cloud email and calendar service that supports many Outlook accounts. Problems with this infrastructure also affected other applications that depend on it.
The company said the incident could affect Microsoft 365 connectivity in different regions. Its investigation identified problems with servers that had become unexpectedly unavailable, placing additional pressure on the remaining infrastructure. Microsoft attempted to restore services by restarting affected servers, redirecting traffic to alternative infrastructure and adjusting its deployment and traffic management processes. However, some servers that had initially recovered became unresponsive again when they received additional traffic.
The company's investigation found that a core process on affected servers was becoming overwhelmed, causing the servers to stop responding and reducing available capacity. Microsoft also examined network configuration changes associated with the start of the disruption. On Friday, Microsoft said its latest measures to improve service stability were not producing the expected results. Engineers were exploring alternative ways to increase capacity and address continuing traffic management problems. The company continued investigating the server failures as disruptions affected users across several regions.
Microsoft had not confirmed that all affected services had returned to normal. It said it would provide more information about the underlying cause and measures to prevent similar incidents in a post incident report after services were restored. The disruption also affected some functions of Microsoft Teams. While Microsoft restored an earlier Teams disruption in North America, certain features relying on Exchange Online, including calendar functions, could still experience problems.
Other Microsoft services, including SharePoint, Copilot, Planner and some business and security management tools, also experienced disruptions. However, the impact varied between services, and not all their functions were affected. The incident also extended beyond Microsoft's own products. Artificial intelligence companies OpenAI and Anthropic reported problems with their Microsoft 365 connectors.
These connections allow their artificial intelligence services to interact with workplace information, including organisational emails and other data. The disruption affected the ability to establish new connections and use certain connected tools. However, the reported problems did not mean that the entire services operated by OpenAI or Anthropic had stopped working.
In Japan, Deputy Chief Cabinet Secretary Masanao Ozaki confirmed on Friday that the disruption had affected the government's shared digital working infrastructure, known as Government Solution Services. The system provides a common working environment for government agencies and their employees. Japanese authorities said they were monitoring Microsoft's response and using alternative arrangements to maintain essential operations.
Japan's government online portal also warned that users could experience delays or fail to receive certain notification emails because of the disruption. These included messages relating to electronic applications, administrative procedures, account registration and password changes. Users were advised to check relevant information through the portal where possible. Microsoft said it was not aware of any malicious activity causing the incident. Its investigation focused on infrastructure failures, server stability and network configuration issues. The company had not announced a definitive root cause.
The incident highlights the growing dependence of businesses, government institutions and other organisations on cloud computing services. Microsoft 365 is widely used for communication, document management, meetings and administrative work. Problems with its underlying infrastructure can therefore affect many connected organisations. The disruption also demonstrated how technical problems at a major technology provider can affect services operated by other companies. With recovery efforts continuing on Friday, users and organisations were waiting for confirmation that services had been fully restored. Microsoft said it would continue monitoring its infrastructure and provide further information as its investigation progressed.