Microsoft is continuing efforts to restore its services following a major global outage that disrupted access to Outlook, Teams, Copilot and several other Microsoft 365 applications.

The disruption began on Thursday (November 12th), with users across the UK, Europe, North America and Asia reporting difficulties accessing email, collaboration tools and other cloud-based services.

The outage has affected businesses, government agencies and public sector organisations, with problems continuing into Friday morning as Microsoft works to restore normal operations.

According to outage monitoring website Downdetector, reports of problems with Outlook peaked at approximately 130,000 on Thursday. It is worth noting though, that figure reflects reports submitted to the platform rather than the total number of affected users.

Which Microsoft services have been affected?

The disruption has primarily affected Exchange Online, Microsoft’s cloud-based email platform, with users reporting difficulties accessing mailboxes through Outlook’s desktop and web applications, alongside delays in sending and receiving emails.

However, the impact has extended across Microsoft’s wider ecosystem.

Microsoft confirmed that Exchange-dependent features within Teams, including calendar access and meeting scheduling, were affected, although core messaging and online meetings seems largely unscathed.

Users of Microsoft 365 Copilot also reportedly experienced difficulties accessing the AI assistant and retrieving information from connected workplace applications.

Additional services affected included SharePoint Online, Microsoft Intune, Planner, and elements of Microsoft Defender and Microsoft Purview, although the extent of disruption varied between applications.

Businesses and public services affected

The outage has caused disruption to organisations worldwide, including government departments, schools and public services.

In the UK, several police forces reported difficulties with online crime reporting, while some NHS organisations experienced disruption to email and other IT services.

The University of Bath also reported that Outlook remained inaccessible to staff on Friday morning, although basic Teams functionality appeared to be working.

Internationally, government agencies in Australia and Japan reported problems accessing Microsoft services, while airlines and other businesses introduced alternative communication arrangements.

What’s causing the outage?

Microsoft initially attributed the connectivity problems to elevated loads across portions of its infrastructure.

Further investigation identified that a number of servers had unexpectedly become unavailable, placing additional pressure on remaining systems and contributing to connectivity failures.

Engineers subsequently identified a process responsible for establishing secure connections that was becoming overwhelmed, preventing affected servers from responding to requests.

Recovery efforts have included restarting affected servers, redistributing traffic across Microsoft’s global infrastructure and adjusting configurations to improve stability.

The company has also said there is no indication that malicious activity caused the incident.

What’s the latest on recovery?

In an update on Friday morning (13th November), Microsoft reported improvements following the deployment of a patch targeting an authentication and routing component.

However, a subsequent update at approximately 9am GMT indicated that, despite early signs of stabilisation, service capacity had not yet returned to normal levels.

Recommended

• CFOs Are Confident in AI’s Business Impact, Deloitte Finds
• Comment | The AI Power Shift: Finance Takes The Lead
• Comment: AI and chatbots | Key issues and risks for employers

Microsoft said its engineering teams were continuing to restore affected infrastructure through a controlled process of restarting servers, applying fixes and gradually reintroducing traffic.

The company has also extended its email timeout window to 48 hours to help preserve delayed messages while recovery continues.

Although some services are beginning to stabilise, Microsoft has yet to confirm a complete restoration.

The company said it would publish a post-incident report outlining the root cause and further technical details once the incident has been resolved.

Further updates are available through the Microsoft service health dashboard.