The incident has been confirmed by outage tracker Downdetector, which logged reports from 74 countries and territories within approximately one hour of the start. In the United States alone, the platform recorded nearly 130,000 reports of Outlook problems shortly after 1 p.m. EST (1800 GMT). Microsoft 365, a cloud-based subscription service that includes Outlook, Teams, and the AI assistant Copilot, is utilized by over 430 million people, according to the company’s website. The scale of the disruption has had tangible real-world consequences; Britain’s National Health Service (NHS) reported a “serious impact” on its operations, while Germany’s rail operator Deutsche Bahn stated that the outage made it difficult to distribute timetables for diverted trains.
Microsoft initially identified that a “portion of infrastructure is experiencing elevated load across multiple regions,” which it believed was contributing to connectivity errors. However, the company later clarified that this elevated load was not caused by an increase in user traffic. Instead, the strain resulted from a number of servers that “unexpectedly” became unavailable, placing additional demand on the remaining infrastructure. Technicians are also addressing a separate issue where servers were becoming unavailable after failing automated health checks, a mechanism designed to monitor system stability.
In a statement posted on X, Microsoft confirmed it was “not aware” of any malicious activity that could have caused the outage. The company emphasized that it is treating the incident with “urgency and priority until full resolution.” By Friday morning, Microsoft reported “encouraging recovery progress,” noting that service availability and email delivery performance were improving across a growing portion of the affected infrastructure. Specifically, service in Europe and Japan was becoming more stable, while North American services were also showing signs of improvement. However, the company warned that some users may still experience intermittent issues as recovery actions continue.
The technical complexity of the outage is evident in Microsoft’s admission that monitored changes applied to improve serviceability were “not taking as expected.” This suggests that standard remediation procedures were insufficient to immediately resolve the underlying connectivity errors, prompting the company to seek alternative solutions. The impact extends beyond core email and messaging; the outage also affected Microsoft 365 connectors used by major AI companies, including OpenAI and Anthropic, which reported that their tools were not working as expected due to the disruption.
For users, the immediate concern is the backlog of undelivered messages. Microsoft stated that reducing email queues and backlogs remains its primary priority. To prevent data loss during the recovery period, the company has kept an “extended 48-hour email timeout window” in place. This measure helps protect delayed messages, ensuring they are not discarded while delivery systems catch up. In practical terms, users in regions where service has partially returned, such as the NBC 5 Chicago newsroom, have reported that while emails are hitting inboxes, there are significant lag times, with some messages taking up to 30 minutes to send and receive.
This is the second major disruption to Microsoft 365 services this year, raising questions about the resilience of the platform’s infrastructure. The incident highlights the critical dependency of global operations on cloud-based communication tools. For businesses and public service organizations, the downtime represents more than an inconvenience; it disrupts workflows, delays critical communications, and in the case of the NHS, impacts operational safety. Microsoft’s transparency in acknowledging that the fix is not proceeding as planned offers a realistic timeline for users, who should expect intermittent connectivity issues until the server health checks and load distribution issues are fully resolved.
As of Friday morning, Microsoft said it would release further updates on the status of the outage, with the next scheduled update at 7 a.m. CT. The company continues to work on restoring full consistency across all affected regions, with the goal of eliminating the remaining areas of disruption and ensuring that email delivery performance returns to normal levels for all 430 million users of the platform.
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