Microsoft services faced a major global disruption on Friday, November 13, leaving thousands of users unable to access Outlook, Microsoft 365 and several other applications. The incident also affected Microsoft Copilot and connections used by third-party artificial intelligence platforms.
The disruption continued for more than 11 hours, affecting users who rely on Microsoft’s services for workplace communication, email and daily business operations.
According to outage-tracking platform Downdetector, reports of problems with Outlook surged to approximately 138,058 around 1:30 a.m. on Friday. The number later dropped to around 34,490 by 4:30 a.m., indicating a gradual improvement in reported service disruptions.
Microsoft acknowledged the issue and said it was investigating problems primarily affecting Exchange Online, the cloud-based email service behind Outlook.
The company identified an overloaded process responsible for establishing secure connections on affected servers. According to Microsoft’s investigation, the process became overwhelmed, preventing some servers from handling incoming requests properly.
Microsoft engineers began working on several recovery measures, including increasing server capacity and restarting affected infrastructure. The company also started scaling up virtual machines to distribute workloads and reduce pressure on its systems.
Another part of the recovery effort involved synchronizing recent network configuration changes on servers that had entered a faulty state. However, Microsoft reported that some machines were not responding as expected, slowing down the restoration process.
The company was also reversing a recent network configuration change that coincided with the beginning of the disruption. Temporary traffic restrictions were introduced in certain locations while engineers monitored server stability before gradually allowing more connections.
The Microsoft outage affected several products beyond Outlook. Exchange Online users experienced difficulties accessing their mailboxes through web browsers, desktop applications and mobile devices. Some users also reported delayed email delivery.
Microsoft 365 users faced problems opening recently accessed files, while certain sections of the Microsoft 365 admin center failed to load.
Copilot was also among the affected services. Users reported problems opening Copilot Chat and receiving responses through its web and desktop applications. Access to workplace information, including emails, calendars and files, was also disrupted.
Microsoft Teams continued to support its main messaging and online meeting functions for many users. However, features connected to Exchange Online, including calendar access and meeting scheduling, experienced problems.
Other affected services included SharePoint Online, Microsoft Planner, Microsoft To Do, Microsoft Defender, Microsoft Purview, Microsoft Graph, Power BI, Microsoft Fabric and Windows 365.
Some Microsoft 365 Education features, including Assignments, Reading Progress and Speaker Progress, were also affected. Certain Microsoft Intune services experienced disruptions as well.
Microsoft clarified that applications and features not dependent on Exchange Online continued to work during the incident.
The impact extended beyond Microsoft’s own products. OpenAI reported investigating problems with its Microsoft connectors, which prevented some users from establishing new connections and caused certain tools to malfunction.
Anthropic also confirmed an issue involving an upstream provider that affected its Microsoft 365 connector.
The disruption created problems for businesses relying on Microsoft’s cloud infrastructure. Electric truck manufacturer Workhorse Group postponed its third-quarter financial results announcement from November 12 to November 16, citing business disruptions caused by the global incident.
Microsoft continued publishing updates through its Microsoft 365 Status account on X, explaining the recovery measures and infrastructure changes being implemented by its engineering teams.
The incident comes just weeks after another disruption involving Microsoft’s Azure cloud platform, which affected productivity applications and businesses across multiple industries.
