Microsoft's cloud productivity suite suffered a major global outage on Thursday, knocking out Outlook, Teams and its Copilot AI assistant for millions of users around the world. The disruption began at about 1:26 pm Eastern Time on Thursday, 12 November, and dragged on for much of the US working day.
Reports of problems with Outlook peaked at nearly 130,000 on the outage-tracking website Downdetector shortly after 1 pm Eastern Time, while Microsoft 365 recorded more than 47,000 reports. The disruption went global within an hour, affecting users in 74 countries and territories across the Americas, Europe, Asia and Africa, according to Downdetector.
Microsoft said a portion of its infrastructure was experiencing elevated load across multiple regions, which it said was likely contributing to the connectivity errors. In updates posted through its Microsoft 365 Status account, the company later explained that a group of servers had become unavailable after failing automated health checks, pushing extra load onto the servers that were still running and overloading Exchange Online, the service behind Outlook email.
The outage affected a wide range of services beyond email. Users reported trouble with Outlook, Teams, Word, Excel, PowerPoint, SharePoint, OneDrive and the Copilot assistant, and Microsoft's own incident notice, coded MO1550821, listed Exchange Online, Microsoft Teams, SharePoint Online, Microsoft 365 Copilot and Microsoft Defender XDR among the services customers might be unable to connect to. The Azure cloud platform and the Microsoft Store were also reported to be affected.
Microsoft said it had paused all deployments and configuration changes, was moving additional traffic off the affected infrastructure and was restarting affected servers to return them to service. By around 6 pm Eastern Time, the company said it was observing limited recovery and that a portion of the affected servers had begun returning to service and remained stable so far, while cautioning that restoration would be gradual as applications reconnected.
Teams was reported to have been restored in North America, according to the Associated Press, although some users continued to experience connectivity problems. Downdetector reports had fallen to about 37,000 for Outlook by 6 pm Eastern Time, and to roughly 34,500 by the early hours of Friday in India, a sign that the worst of the disruption was passing.
The outage also rippled beyond Microsoft's own products. OpenAI said it was investigating an issue affecting its Microsoft connectors, with new connections potentially failing and some tools not working as expected, and Anthropic reported an issue with an upstream provider affecting its Microsoft 365 connector, highlighting how widely shared cloud infrastructure can spread a single failure.
Microsoft has not provided a definitive cause for the wider outage and has not given a specific timeframe for when all services will be back to normal. The company said it was testing a fix and was checking whether a recent update played a part in the failure.
For businesses, the outage was a reminder of how dependent daily work has become on a small number of cloud platforms. Email, meetings, documents and AI assistance all stopped at once for many organisations, and with no immediate workaround, staff were left waiting for Microsoft's engineers to bring the servers back.
Microsoft 365 is the company's subscription-based productivity platform, bringing together Outlook, Teams, Word, Excel, PowerPoint, SharePoint and OneDrive, and it is used by hundreds of millions of people. The company is expected to publish a fuller account of what went wrong once its investigation is complete.
