Microsoft 365 suffered a global service outage. Microsoft announced that services had been fully restored on the afternoon of the 14th Taiwan time, around 36 hours after the first reports of problems. Microsoft apologized and explained that the issue stemmed from an earlier network capacity expansion, and was unrelated to a cyberattack or AI. A full post-incident report will be published after the internal review is complete. (Read more: Outlook suffers a major global outage, leaving employees stunned: emails won’t send, meetings can’t be scheduled on Teams, and Copilot is down too) (Background: Four major AI services suffer global outages, making people realize just how severe their dependence has become) Key points - Microsoft announced on the afternoon of the 14th that services had been fully restored, after an outage lasting around 36 hours. - Microsoft said the issue stemmed from an earlier network capacity expansion and was unrelated to a cyberattack or AI. - Within about an hour of the incident, reports of problems had come in from 74 countries and regions. Microsoft has fully restored its services following the global outage. At 2:09 p.m. Taiwan time on the 14th, the Microsoft 365 Service Status account said the root cause of the incident had been addressed. Service had also been restored for the remaining affected customers and regions. Around 36 hours had passed since the first report of a problem at 1:54 a.m. on the 13th. As of the evening of the 14th, Microsoft's service status page showed “All products are operational,” and its consumer products section was also marked as normal. Microsoft said at 2 a.m. on the 14th that services had been broadly restored, but it took around another 12 hours before the company announced that the issue was resolved. Microsoft explained that the outage had a serious impact, requiring an extended monitoring period. It also had to wait until all the emails that had piled up during the incident were processed before declaring the issue resolved. The outage began with Exchange Online, Microsoft's enterprise email service. Outlook users could not connect to their mailboxes, and emails were delayed. Scheduling meetings in Teams and using Microsoft 365 Copilot were also affected. Downdetector, a website that tracks service outages, received reports from 74 countries and regions within about an hour of the incident. Microsoft's stock rose 0.36% and 0.17% at the close of U.S. trading on the 12th and 13th, respectively, showing almost no reaction. The issue stemmed from an earlier network capacity expansion Microsoft apologized on X in the early hours of the 14th, saying it was “deeply sorry” for the disruption the incident had caused customers and partners. The company explained that the problem originated during an earlier network capacity expansion and only surfaced after a more recent network change. Microsoft stressed that this was a technical issue, unrelated to a cyberattack, AI, or AI agents. We are deeply sorry for the disruption this incident has caused our customers and partners. We know the trust they place in our services and take that responsibility extremely seriously. We are seeing broad recovery and stability across our services. This was a technical issue… — Microsoft 365 Status (@MSFT365Status) November 13, 2026 In the same post, Microsoft said that due to high demand, services were being restored in stages, with stability confirmed at each stage before moving on to the next. Microsoft said this approach was slower, but helped ensure a stable recovery. Cascading failures slowed the recovery Charles Lamanna, Microsoft's executive vice president in charge of Copilot, AI agents, and platforms, also explained the situation on X early on the 14th. He said the investigation pointed to cascading failures, compounded by a “thundering herd” effect at the network edge, which made recovery more difficult than usual. A thundering herd effect occurs when a large number of connections flood a service at the same time as it recovers. Lamanna said Microsoft would publish a post-incident review report soon, including a detailed timeline and several fixes to prevent similar outages. Microsoft said the full report would be published after the internal review was complete, but no publication date had been announced. Frequently asked questions What caused the Microsoft Outlook and Teams outage? Microsoft said the roughly 36-hour outage was caused by a problem that arose during an earlier network capacity expansion and surfaced after a more recent network change. It was unrelated to a cyberattack or AI. The full post-incident report will be published after the internal review is complete. How long did the Microsoft 365 outage last? Microsoft first reported a problem at 1:54 a.m. Taiwan time on the 13th. At 2:09 p.m. on the 14th, it announced that the root cause had been addressed and service restored for the remaining affected customers and regions. The outage lasted around 36 hours in total. Related stories The mystery of three AI services—Claude, OpenAI, and Grok—going down at the same time: Shared data centers? DeepSeek suffered a five-hour outage yesterday: The company says it will refund API fees from the previous week as compensation, using credits. Websites for Taipei City Government departments and the 1999 hotline all went down overnight: They were tied to the same system, so a single point of failure took everything offline. “Microsoft 365 suffers a major 36-hour outage! Services fully restored; company says issue stemmed from network capacity expansion” was first published by BlockTempo (動區動趨—The most influential blockchain news media).