Microsoft experienced a widespread service disruption after a cascading software issue rendered a large number of its servers unexpectedly unavailable. The problems began on Thursday, initially reported in the U.S. and the Americas, but they rapidly spread worldwide as engineers worked to restore affected servers.
Services impacted
The incident started as an outage of Outlook email and Teams video conferencing and escalated into broader failures across Microsoft’s cloud services. Both consumer and business email, file and document services were affected, as were Copilot AI tools and the Defender security scanner. System administrators reported difficulties accessing internal Intune dashboards and features, and some users encountered problems reaching cloud-hosted Windows machines.
The outage disrupted a wide range of organizations; for example, TechCrunch’s own email was affected. Microsoft did not respond to questions asking whether it has technical means, such as logs, to detect malicious activity or to explain exactly how it is investigating the incident.
Investigation and recovery
Microsoft has said the outage involved “a large number of servers being unexpectedly unavailable” and that it is continuing to investigate the root cause. In a Friday status update the company stated there was “no evidence of malicious activity associated with this incident.”
By Friday morning on the U.S. east coast, Outlook service had begun to recover and some emails were arriving. Doug Madory, director of internet analysis at Kentik, wrote on Bluesky that traffic was returning to Microsoft’s services after about 18 hours of downtime.
Context
This is not Microsoft’s first major recent outage. In September, Microsoft experienced a days-long disruption to its cloud services that the company attributed to a “core authentication configuration” issue that prevented users from accessing services.
The story was first published on November 12 and has been updated as new information became available.
