A widespread Microsoft outage has disrupted business communications and other essential services across multiple regions, with users experiencing problems accessing Outlook, Teams and other Microsoft 365 applications.

The disruption began on Thursday 12 November, initially affecting Exchange Online, Microsoft's cloud-based email service, before spreading to other applications and services. These included SharePoint, OneDrive, Microsoft 365 Copilot and elements of Microsoft’s security and administration platforms. Some Teams functions, including calendar and meeting scheduling, were also affected, although core messaging and online meetings remained largely operational.

Microsoft’s investigation has identified problems with the infrastructure supporting its services, with a number of servers becoming unexpectedly unavailable and placing additional pressure on the remaining systems.

The company said a process responsible for establishing secure connections on affected servers had become overwhelmed, while automated health checks were also causing some servers to be taken out of service. It has been restarting affected infrastructure, redirecting traffic and testing configuration changes to restore capacity.

In its latest service updates overnight on Thursday, Microsoft reported positive results from efforts to restart affected systems, but said it was continuing to monitor their stability before extending the recovery measures. The company said it is not aware of any malicious activity causing the incident and will give full details of the root cause once it has been mitigated in a post-incident report.

The company’s service health dashboard continued to report degradation affecting Microsoft 365 services on Friday morning.

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