Microsoft Outlook email stopped working for users around the world on Thursday, 12 November, after a large number of the company’s servers became unexpectedly unavailable. The disruption spread into Teams, SharePoint and other Microsoft 365 services, and recovery was still gradual hours later.
Reports of trouble began just before 1pm Eastern Time, with people unable to reach their inboxes through the web or apps. Business and consumer users were both affected, and the problem soon reached beyond the Americas to other regions. Outage tracker Downdetector recorded almost 130,000 reports about Outlook at the peak, according to reports.
The failure was not limited to email. Microsoft said its video calling tool Teams, file sharing platform SharePoint and artificial intelligence tool Copilot were also unavailable, along with the Defender XDR security system. Consumers also lost access to OneDrive storage, Office for the web and several other services.
Microsoft first blamed elevated load across parts of its infrastructure, then said a large number of servers had become unexpectedly unavailable. It later said it was testing a configuration change aimed at servers failing automated health checks, and restarting affected machines in stages. Its communications director, Ben Hope, said the company was aware of the reports and working to restore services as soon as possible. The incidents are tracked as EX1550543 and MO1550821 in the Microsoft 365 admin centre.
Recovery under way, but no finish time
By about 6pm Eastern Time, Microsoft said it had begun returning some affected servers to service and that they were remaining stable. It had shifted traffic to alternative pathways and reported limited recovery in some regions, with users expected to reconnect gradually as capacity returned. The company warned, however, that restored servers could become unresponsive again once they started taking traffic, and it gave no time for full restoration.
The disruption arrived only weeks after Microsoft unveiled new Surface hardware at its autumn showcase. When the cloud side fails, the hardware in front of a worker cannot help.
A reminder of how much rides on one inbox
For millions of workers, the inbox is where the working day begins, and this is the second major Microsoft 365 failure in about two months. In September, a days-long outage hit the same suite, which Microsoft blamed on a core authentication configuration problem. Two large failures in such a short period will raise questions about the resilience behind a service that so many businesses treat as basic infrastructure.
Microsoft has said there is no indication of a cyber attack behind the outage, and it has not yet published a full root cause. Until it does, users can check the company’s public status page, and administrators can follow the incident references in the Microsoft 365 admin centre.
