Microsoft Blames Network Upgrade for Global Outage, Rules Out AI or Cyberattack
Microsoft confirmed that a technical issue during a network capacity upgrade caused the global Microsoft 365 outage, explicitly excluding AI or cyberattack involvement.
US tech giant Microsoft stated on November 13 that its Microsoft 365 cloud services have largely recovered after a widespread outage lasting approximately 24 hours. A company spokesperson clarified that the incident was triggered by an issue during an earlier network capacity upgrade, which surfaced following a recent network change, explicitly ruling out cyberattacks or AI agents as causes.
The disruption began around noon Eastern Time on Thursday, initially affecting North America before spreading to more than 70 countries worldwide. Impacted services included Outlook email, Teams collaboration platform, and the Copilot AI assistant. The outage significantly disrupted critical sectors such as aviation, hospitals, and law enforcement, given the heavy reliance of businesses and governments on these tools.
To manage the backlog of emails sent during the downtime, Microsoft increased the email queue time to 48 hours to ensure delivery of all attempted messages. Independent researcher Jonathan Leitschuh warned that users might experience a flood of notifications and delayed emails over the next few hours as subsystems come back online.
While services are being restored, the episode underscores the risks associated with global digital infrastructure's dependence on a single vendor. Microsoft has promised a full post-incident report after completing its review.