Microsoft is still battling a major global outage affecting Microsoft 365, one that has dragged on for over ten hours and shows no sign of a clean resolution. Systems that appeared to be restored are now failing when traffic resumes, and engineers are scrambling to patch the core issue. The trouble began November 12, 2026, starting with Exchange Online failures in the Americas and swiftly spreading to Outlook, Teams, SharePoint, Copilot, and Microsoft Defender XDR in virtually every region.
What’s Causing the Failures?
When Microsoft brings servers back online, they function briefly—until user traffic hits them. That surge causes them to become unresponsive again. Despite restarting servers, pausing updates, and diverting load to other parts of its infrastructure, none of those tactics have maintained stability under load.
Several recovery paths are now underway. Microsoft is temporarily limiting certain types of traffic reaching affected systems, rebuilding some servers using previous configurations, and rerouting or blocking traffic strategically. These measures are helping in some locations, with partial recovery reported, though service remains spotty and email delivery still delayed.
Scale of the Chaos
More than 120,000 issues were reported to outage tracker Downdetector, especially concerning Outlook, with complaints coming from at least 74 countries. Affected services include Exchange Online, Teams, SharePoint Online, Copilot, Defender, Planner, To Do, Intune, Purview, and Power BI. Only features not relying on Exchange seem untouched, though downstream effects are felt elsewhere—integrations like those with OpenAI and Anthropic have also suffered.
Microsoft has made clear the outage is not the result of a cyberattack or security breach. Causation is unknown. Diagnostic efforts are underway, and a risk has been identified in a core process that’s being overwhelmed. Microsoft is monitoring the behavior, verifying stability in isolated infrastructure segments before scaling fixes.
What Admins Should Do Now
Local troubleshooting is unlikely to help—this is an issue on Microsoft’s side. Administrators are advised to follow updates for incident IDs EX1550543 and MO1550821 via the Microsoft 365 admin center or the alternative status page. Avoid password resets, profile rebuilds, or tenant setting changes. Be ready for intermittent recovery and delays in email delivery once systems return. There’s also warning signs of phishing campaigns or fake support calls taking advantage of the chaos.
Microsoft expects gradual restoration as the fixes roll out. But with servers dropping repeatedly under load, the company is treading cautiously—restoring services bit by bit while closely observing performance.
This outage underscores a rising risk in relying on massive, interdependent cloud infrastructure. When something goes wrong deep in the stack, even standard recovery tools—restarts, rerouting, patching—can fail to hold when demand returns. Watch for Microsoft’s next root cause report and engineering post-mortem to reveal what regulatory or architectural changes might come. For users and companies alike, it’s time to re-evaluate assumptions about cloud redundancy, incident response, and trust in enterprise-grade SLAs.
