A major global Microsoft outage is disrupting access to Outlook email, Microsoft Teams and a range of Microsoft 365 cloud services, with the technology company confirming that unexpectedly unavailable servers have placed additional pressure on its remaining infrastructure.
The disruption, which began on Thursday 12 November in the United States and continued into Friday morning in Australia, has affected enterprise communications, email access, collaboration platforms and cloud-based business applications.
Microsoft has acknowledged connectivity problems affecting Exchange Online mailboxes and multiple Microsoft 365 services, including SharePoint Online, Microsoft 365 Copilot, Microsoft Defender XDR, Planner, To Do, Intune, Purview and Power BI.
Users have reported being unable to access email accounts, send or receive messages, load inboxes or connect to Microsoft cloud applications. Outage monitoring service Downdetector recorded nearly 130,000 reports of Outlook problems at the height of the disruption, although the figures represent user-submitted reports rather than a confirmed count of affected customers.
Microsoft identified elevated infrastructure loads as a contributing factor, with a significant number of servers becoming unavailable and transferring demand to other parts of its cloud environment.
In a service health update, Microsoft stated:
“We’ve determined that the elevated load isn’t driven by an overall increase in traffic, but by a large number of servers being unexpectedly unavailable, which is shifting load onto the remaining infrastructure.”
The company said it was investigating why the servers had become unavailable while working to restore them safely.
Microsoft subsequently identified failures in automated server health checks and began testing an alternative process to return affected servers to operation.
By Thursday evening US time, Microsoft reported that an alternative health-check method had successfully restored a subset of affected servers and was being deployed more broadly.
The company also began restarting and validating affected infrastructure, while investigating whether recent configuration changes contributed to the incident.
Microsoft said it had temporarily suspended deployments and configuration changes as a precaution while its engineers examined potential causes.
In a further update, the company said:
“We’re aggressively pursuing all pathways to reduce impact.”
Microsoft also confirmed that it was evaluating whether reversing a limited number of recent configuration changes could accelerate recovery.
The outage has raised questions about the resilience of widely used cloud services and the operational consequences for organisations that depend on a single technology provider for email, collaboration, identity management and business applications.
For Australian organisations, the incident highlights the potential for failures within globally distributed cloud infrastructure to affect local operations, even where customers have not experienced problems with their own networks or systems.
The reported disruption to Microsoft Defender XDR and other enterprise services is also relevant to security operations teams, which may depend on cloud-hosted platforms for threat detection, incident investigation and response coordination.
Microsoft’s published incident information identifies Exchange Online incident EX1550543 and broader Microsoft 365 incident MO1550821. The company has not confirmed a cyberattack as the cause of the disruption, and the available evidence points to an infrastructure availability problem rather than a confirmed malicious security incident.
The incident comes five months after the Australian Government announced a new partnership with Microsoft intended to strengthen the resilience of cloud infrastructure, critical government systems and Australia’s broader digital ecosystem.
On 10 June 2026, Minister for Home Affairs and Cyber Security Tony Burke announced a memorandum of understanding with Microsoft covering hyperscale cloud resilience, critical infrastructure, secure artificial intelligence and emerging cyber threats.
At the time, Burke said, “Microsoft is a critical partner in cyber security, and this agreement takes our relationship to the next level.”
The agreement also recognised that disruptions to digital systems could have rapid and widespread consequences, requiring closer cooperation between government and industry.
The outage has also affected services beyond Microsoft’s own applications. OpenAI reported problems with Microsoft connectors, while Anthropic identified an upstream provider issue affecting its Microsoft 365 connector, demonstrating the outage is affecting third-party applications and integrated services.
Microsoft has reported progress restoring affected servers, but a complete restoration of all impacted services had not been independently verified at the time of publication.
The incident remains under investigation, with Microsoft continuing to examine server health-check failures, infrastructure load and possible configuration-related causes.
For organisations relying on Microsoft 365, the outage reinforces the importance of maintaining alternative communications arrangements, documented business continuity procedures and independent access to critical operational information during major cloud service disruptions.
