Microsoft apologized Friday for a massive outage that disabled Outlook, SharePoint, Copilot, and other Microsoft 365 services. The connectivity problems began shortly before 1 p.m. ET on Thursday and lasted nearly 24 hours.
The outage stemmed from "an issue during an earlier network capacity upgrade," Microsoft said. The company initially blamed elevated server load across multiple regions and failures in automated health checks, but stated it detected no malicious activity. By Saturday, Microsoft said it had addressed the underlying issue and restored service to remaining customers and regions.
Outlook and other Microsoft 365 tools were largely down during Friday morning U.S. hours and throughout Asian and European business days. Services began returning online Friday morning. Microsoft extended the timeout window for delayed emails to 48 hours to help protect messages caught in queues during recovery.
The outage disrupted hospitals, airlines, and businesses globally. The U.K.'s National Health Service said some services were affected. Workhorse Group delayed third-quarter earnings reporting from Nov. 12 to Nov. 16 due to the disruption. Richemont's earnings release was slightly delayed. Air India temporarily rerouted emails but said flight operations were unaffected.
Microsoft said it would issue a full report after completing its assessment. The company reported in 2025 that Copilot had more than 100 million monthly active users.