Microsoft's global outage stretched into Friday after restored servers became unresponsive again when traffic returned, prolonging disruption to Outlook, Teams, Copilot and connected AI services. The incident began around 16:17 UTC Thursday within Exchange Online and remained widespread more than 12 hours later. Downdetector recorded between 130,000 and 140,000 Outlook problem reports at peak, likely an undercount because most users do not report issues. Microsoft said a number of servers were unexpectedly unavailable, placing strain on remaining systems, and found no indication of malicious activity.
The company initially described positive results from restarting affected infrastructure, but by 3:13 a.m. GMT Friday said changes were not taking effect as expected. Engineers investigated other ways to add capacity and redirected traffic while administrators tracked updates under EX1550543 and MO1550821. The outage affected Microsoft 365 services tied to Exchange Online, including Outlook, SharePoint, Teams and Copilot; some users could not access files or calendar details, though messaging and online meetings remained largely functional.
The disruption spread beyond Microsoft's own apps. OpenAI said it was investigating an issue affecting Microsoft connector connections, while Anthropic reported failures in its Microsoft 365 connector for email, calendar and search, as well as Claude for Outlook. Schools, courts and businesses in the US and Australia were affected; Indian airlines IndiGo and Akasa Air reported customer email disruptions, and Taiwanese financial institutions including an unnamed company cancelled a planned bond repurchase. Electric-truck maker Workhorse Group postponed its quarterly earnings call to 16 November, citing the outage. Microsoft stock closed Thursday at $523, up 0.36%, with eToro analyst Josh Gilbert saying enterprises cannot easily abandon deeply embedded Microsoft systems. RMIT University academic Mark Gregory described a 'cascading problem' as restored servers failed again under renewed load.
