A significant Microsoft 365 outage on November 12, 2026, disrupted critical workplace applications, including Outlook, Microsoft Teams, SharePoint, and Copilot, for users across 74 countries and territories. The incident, which Microsoft confirmed was due to internal infrastructure failures rather than a cyberattack, led to a cascading loss of cloud capacity.
Outage Timeline and Global Impact
The disruption to Exchange Online began at 16:17 UTC, quickly escalating to a global issue. User complaints on outage-tracking platform DownDetector surged dramatically, peaking at 19,650 reports per minute across five combined Microsoft services by 18:25 UTC. This was a stark contrast to fewer than 15 reports per minute on an average day.
Reports of the outage spread rapidly beyond the Americas, with significant spikes noted in the UK, India, and New Zealand. While core business services were severely affected, consumer-facing platforms like Xbox, GitHub, and LinkedIn experienced comparatively minor issues. Even Microsoft’s public service status dashboard briefly went offline under the strain.
Root Cause: Internal Infrastructure Failure
Microsoft attributed the outage to a series of internal infrastructure failures. A large pool of servers unexpectedly failed automated health diagnostics and went offline. As user traffic was automatically redirected to the remaining active servers, a core process became overwhelmed by elevated processor usage. This led to a domino effect, causing otherwise healthy servers to become unresponsive.
“We're testing a configuration change to address a problem that's causing servers to fail automated health checks and become unavailable,” Microsoft stated in an update on X, confirming that restarts across affected machines had been initiated.
Recovery Efforts Underway
To stabilize the network, Microsoft engineers took several decisive actions. They froze all routine software deployments and configuration updates, rerouted user traffic onto alternative infrastructure pathways, and deployed an alternative health-check method to safely reintegrate restarted servers into the network.
By the evening of November 12, complaint volumes on DownDetector had decreased from their afternoon highs. Microsoft confirmed that recovery was underway, though they cautioned that full restoration would be gradual as capacity was restored and clients reconnected. This marks the third major Microsoft 365 disruption this year, following multi-hour outages in January and a code-update failure in August.