New Delhi, November 13, 2026: A widespread Microsoft service disruption affected thousands of users globally on Friday, leaving several applications, including Outlook, Microsoft 365 and Copilot, inaccessible or partially functional for more than 11 hours. The outage also extended to third-party artificial intelligence platforms OpenAI and Anthropic, disrupting their Microsoft 365 integrations.
According to Downdetector, user complaints about Outlook peaked at approximately 1,38,058 around 1:30 am on Friday. The number subsequently declined to nearly 34,490 by 4:30 am, indicating a gradual improvement in service availability.
Microsoft attributed the disruption to failures in its server infrastructure, identifying an overloaded process responsible for establishing secure connections as a key contributor. The process reportedly became overwhelmed, preventing affected servers from handling incoming requests.
The company has been issuing regular updates on its recovery efforts, with more than 15 communications posted on X since the incident was reported. Its response has included increasing server capacity, modifying network configurations and restarting affected infrastructure.
In its latest update, Microsoft said it was expanding the capacity of virtual machines to distribute workloads more effectively and ease pressure on its systems. It was also attempting to restore machines stuck in faulty states by synchronising recent network configuration changes. However, delays in synchronisation across certain machines have complicated the recovery process.
The company has additionally introduced temporary traffic restrictions in selected locations to stabilise affected servers before gradually restoring normal traffic levels. Microsoft clarified that the disruption was not triggered by an overall surge in user demand but by a reduction in the number of servers available to process requests.
Exchange Online Disruption Affects Multiple Microsoft Applications
The outage primarily affected Exchange Online, Microsoft's cloud-based email platform, with consequences extending to several interconnected applications and services.
Outlook users experienced difficulties accessing their mailboxes across web, desktop and mobile platforms. Email delivery delays and problems retrieving messages were also reported. Microsoft 365 users faced challenges accessing recently used files, while certain sections of the administration centre became unavailable.
Microsoft Copilot was among the affected services, with users reporting problems loading Copilot Chat and generating responses. Its integration with workplace information, including emails, calendars and documents, was also disrupted.
Microsoft Teams retained most of its core communication capabilities, including messaging and online meetings. However, features dependent on Exchange Online, such as calendar access and meeting scheduling, experienced interruptions.
Other affected products included Microsoft Planner, Microsoft To Do, Microsoft Defender, Microsoft Purview, Microsoft Graph, Microsoft Fabric, Power BI, SharePoint Online, Universal Print and Windows 365. Certain Microsoft 365 Education features, including Assignments, Reading Progress and Speaker Progress, were also impacted, alongside selected Microsoft Intune services.
Microsoft maintained that applications and functionalities independent of Exchange Online continued to operate.
OpenAI and Anthropic Report Disruptions to Microsoft Integrations
The incident also highlighted the extent to which third-party technology platforms depend on Microsoft's cloud infrastructure and enterprise services.
OpenAI reported an issue involving its Microsoft connectors, warning that users could experience difficulties establishing new connections and using certain integrated tools. Anthropic similarly identified an upstream service provider issue affecting its Microsoft 365 connector.
The disruption also had operational consequences for businesses. US-based electric truck manufacturer Workhorse Group postponed its third-quarter financial results announcement from November 12 to November 16, citing business interruptions associated with the Microsoft outage.
Another Cloud Disruption Raises Questions About Service Reliability
The latest incident comes just weeks after a disruption involving Microsoft's Azure cloud platform affected its productivity applications and business customers across multiple industries.
The recurrence of large-scale service interruptions underscores the growing dependence of organisations on interconnected cloud platforms, enterprise productivity applications and AI-powered tools. As businesses increasingly consolidate their operations around these ecosystems, disruptions to critical infrastructure can have consequences extending well beyond a single technology provider.
Microsoft continues to monitor the recovery process and assess the effectiveness of the changes implemented to restore services.
