(11-12-26) A Microsoft 365 outage that started late Thursday morning knocked out Outlook and other Microsoft services for users across the United States — and across the Americas — with outage reports topping 130,000 at the peak.
The trouble began around 11:17 a.m. Eastern (10:17 a.m. Central) Thursday, when users started having problems reaching their Exchange Online mailboxes, the service that carries Outlook mail. Microsoft first acknowledged the problem just before noon Central, saying users were “experiencing issues accessing Exchange Online mailboxes through multiple connection methods in the Americas.” It later warned the issue could affect Microsoft 365 service connectivity for users in any region.
Coast to coast
Outage tracker Downdetector, which collects user reports from across the country, logged more than 130,000 reports of Outlook problems by 1:27 p.m. Eastern, along with more than 46,000 reports for Microsoft 365 overall and about 3,000 for Teams. Reports came in from Texas to New York to Michigan and beyond — and from other countries in the Americas as well.
The disruption spread well past email. Microsoft’s status page named Exchange Online, Teams, SharePoint Online, Copilot 365 and Microsoft Defender XDR among the affected services, and users also reported problems with OneDrive and the Microsoft Store. Both business and personal accounts were affected.
State and local governments felt it too. Michigan’s Department of Technology, Management & Budget posted a “SYSTEM OUTAGE” alert Thursday afternoon warning that state email and other Microsoft applications were down and responses would be delayed. Other local governments, including Howard County, Maryland, posted similar notices.
What Microsoft says caused it
Microsoft has not named a root cause, and it has not linked the outage to a cyberattack.
Its explanation shifted during the day. At first the company said a portion of its infrastructure was experiencing elevated load across multiple regions. By mid-afternoon it revised that: the load was not driven by an increase in traffic, but by a number of servers unexpectedly becoming unavailable, straining the infrastructure that remained.
Microsoft said it paused all deployments and configuration changes while it reviews recent changes, redistributed connection traffic across its broader worldwide infrastructure to balance the load, and began restarting affected servers to return them to service. It has given no time for full restoration and has not published a full root cause.
The incident is tracked in the Microsoft 365 admin center as EX1550543, with a wider Microsoft 365 record under MO1550821.
A separate Microsoft Teams disruption in North America earlier Thursday morning was resolved around noon Eastern, about 40 minutes before the wider outage began. Microsoft has not said the two share a cause.
Service coming back
By late Thursday afternoon, outage reports had fallen sharply from their early-afternoon peak, and news reports said service was coming back for most people. Microsoft’s public status page showed all products operational, though the company had not published a formal root cause.
There was nothing affected users could do on their end — the problem was on Microsoft’s side, not with individual computers or networks. Microsoft posts updates first on its Microsoft 365 Status account and on the Service health page in the Microsoft 365 admin center.
Second major outage of the year
Thursday’s outage is the second large Microsoft 365 outage of 2026. On January 22, an infrastructure problem in North America took Microsoft 365 down for close to ten hours before access was restored, according to The Register.
Sources: Microsoft 365 Status; Downdetector; Reuters; USA Today; The Washington Times.
