Follow-Up: Microsoft 365 Outage Continues Worldwide; Outlook, Teams and Other Services Disrupted, Some Servers Back in Service
Microsoft's Microsoft 365 cloud services suffered a worldwide outage on November 12, disrupting Outlook email, Microsoft Teams and several other services for hours. Microsoft said a large number of its servers failed automated health checks and unexpectedly became unavailable, and that a core process on the affected servers later became overwhelmed, causing a loss of capacity. The company said there was no indication the outage was caused by a cyberattack, and that it was not caused by a surge in traffic. As of Thursday evening, Microsoft had not declared the incident over, though a portion of the affected servers had returned to service and remained stable.
User reports surged after noon Eastern. Microsoft first acknowledged the problem at 12:54 p.m. Eastern, saying it was investigating problems reaching Exchange Online mailboxes in the Americas through multiple connection methods, and later said users in any region could be affected. According to Microsoft's service advisory, the affected services include Exchange Online, Microsoft Teams, SharePoint Online, Microsoft 365 Copilot and Microsoft Defender XDR, and the incident is tracked in the Microsoft 365 admin center as EX1550543 and MO1550821.
Data from outage tracker Downdetector showed reports for Outlook peaking at just shy of 130,000 around 1 p.m. Eastern, while reports for Microsoft 365 peaked above 46,000; by about 5:30 p.m. Eastern, roughly 38,000 Outlook reports were still coming in. The Massachusetts state government said its email and other Microsoft services were unavailable, and Australia's National Cyber Security Coordinator said it was monitoring the outage. In Southern California, city services in Culver City and Rancho Palos Verdes were also disrupted during the day.
Microsoft said that around 4 p.m. Eastern, an alternative health-check method had returned a subset of the affected servers to service, that it was applying the method more broadly, and that it was preparing automated systems to continually detect and restart unresponsive servers. Shortly after 5 p.m. Eastern, the company said the steps taken so far had not brought the relief it expected, that a core process on the affected servers was becoming overwhelmed and costing capacity, and that it was isolating part of its infrastructure, restarting components and bringing traffic back to test a possible recovery. By Thursday evening, Microsoft said a portion of the affected servers had returned to service and were remaining stable, with limited recovery in some regions. The company had earlier paused all deployments and configuration changes and shifted traffic to alternative pathways. According to The Register, this is Microsoft 365's second major outage of 2026; one in January lasted almost 10 hours.
Microsoft has not yet published a full account of the outage, and the incident is still developing.
Source: Microsoft
Published by GSM · USA (original Chinese edition)
Photo: 图：微软位于华盛顿州 Redmond 的总部西园区航拍。Jelson25 摄，公共领域，Wikimedia Commons。 / Photo: Aerial view of the West Campus of Microsoft's headquarters in Redmond, Washington. Photo by Jelson25, public domain, via Wikimedia Commons.
- 2026-11-12Nationwide Microsoft Outage Disrupts City Services in Two Southern California Cities: Culver City Hall Slowed, Rancho Palos Verdes Email Down
- 2026-11-12Follow-Up: Microsoft 365 Outage Continues Worldwide; Outlook, Teams and Other Services Disrupted, Some Servers Back in ServiceThis story
- 2026-11-12Microsoft Outage Becomes an 'Adult Snow Day' Online: Outlook Reports Top 130,000 as Workers Joke About the Break
- 2026-11-13Follow-up: Microsoft 365 Outage Enters a Second Day as Capacity Stays Below Baseline and Email Timeout Is Extended to 48 Hours
