Microsoft Corporation reported a resolution to service disruptions affecting its Azure East US region on the morning of April 25, 2026. The incident, which began late in the evening of April 24, primarily impacted the ability of customers to provision new resources, scale existing workloads, or perform management operations. According to the Azure Service Health dashboard, the root cause was traced to a platform-level configuration update that affected the regional control plane, leading to a surge in API request failures.
The disruption began at approximately 21:45 UTC on April 24, 2026. During the peak of the event, customers attempting to deploy Azure Virtual Machines (VMs) or update Azure Kubernetes Service (AKS) clusters encountered error codes 500 and 503. Internal telemetry indicated that provisioning success rates dropped by 45% for compute-related services within the East US geography. While existing workloads remained largely operational, any automated scaling events triggered by traffic spikes were delayed, leading to secondary performance degradation for some end-user applications.
Technical analysis provided by Microsoft’s engineering team identified that a routine update to the Resource Manager (ARM) API gateway, specifically affecting API version 2024-05-01-preview in the East US region, contained a logic error. This error caused a deadlock in the service responsible for validating resource quotas and subscription limits. Consequently, the Azure Portal, Azure CLI, and PowerShell modules were unable to process requests for resource creation or modification. Affected services included Azure SQL Database, Azure App Service, Azure Functions, and Azure Storage accounts.
Microsoft initiated mitigation efforts at 01:15 UTC on April 25 by rolling back the problematic configuration update to a known stable version. By 03:30 UTC, provisioning success rates began to stabilize, and the backlog of queued requests was cleared by 05:00 UTC. Microsoft confirmed that all services had returned to normal operating parameters by 06:00 UTC, totaling approximately eight hours of degraded performance. The company stated that a full Post-Incident Review (PIR) would be published within 72 hours, detailing the specific code-level failure and the measures taken to prevent recurrence in other regions.
The East US region is one of Microsoft’s largest and oldest data center hubs, hosting thousands of enterprise customers across the financial, healthcare, and government sectors. While Microsoft has not disclosed the exact number of affected organizations, the Azure status page noted that the issue was confined to the East US region and did not impact East US 2 or other neighboring zones. This event marks the first significant regional control plane failure for Azure in the 2026 calendar year.