Microsoft Azure

What happened?Between 21:45 UTC and 23:23 UTC on 15 June 2026, Azure customers leveraging services which depend upon Microsoft Artifact Registry (MAR) may have experienced 401 authentication errors when attempting to pull images from MAR .  This incident is now mitigated. Further details will be provided directly to impacted customers through the Azure Portal.

Impact Statement: Starting at 21:45 UTC on 15 June 2026, a subset of Azure customers leveraging services which depend upon MCR (Microsoft Container Registry) for storing images may experience 401 authentication errors for requests attempting to pull Microsoft images from mcr.microsoft.com.Current Status: We detected this issue via internal service monitoring upon identifying a spike of 401 errors. We’ve identified a potential underlying factor to be a recent update which introduced a code regression, and we've completed roll out of a hotfix to address the code regression and mitigate impact for affected customers. We are closely monitoring internal telemetry to validate full mitigation and prevent further occurrences. The next update will be provided within 60 minutes, or as events warrant.

We are actively investigating customer alerts of 401 authentication errors when pulling images from mcr.microsoft.com. We’ve identified a potential underlying factor related to a recent update made to a backed service and we are actively working on determining mitigation workstreams. More information will be provided shortly.

Impact Statement- Starting at 04:27 UTC on 29 May 2026, customers may experience increased latency, intermittent connectivity, or timeouts when accessing resources hosted in the West US 2 region, due to a power event. We are in process of recovering power and working to restore infrastructure in the region. We started seeing partial recovery and will be sending targeted communications to impacted customers through the Azure Service Health dashboard. The next update will be provided within 60 minutes.

Impact statement: Starting at 04:27 UTC on 29 May 2026, a severe thunderstorm caused widespread utility power loss across multiple West US 2 datacenter facilities, resulting in impact to multiple Azure services. Datacenter power has been fully restored, and the majority of network and storage infrastructure has recovered. Infrastructure in Availability Zone 2 has recovered and is operating normally. Residual impact is now concentrated on a subset of infrastructure within Availability Zones 1 and 3, where two storage stamps are undergoing final recovery and validation. Customers with resources deployed exclusively in Availability Zone 2 should not be affected by the remaining recovery activities; however, those with dependencies in Availability Zones 1 or 3 may continue to experience intermittent connectivity, elevated latency, or resource unavailability.The following Azure services are in the final stages of recovery:Azure SQL, Virtual Machines, Virtual Machine Scale Sets, Azure Kubernetes Service, Application Insights, Azure Monitor, and Azure Log Analytics.The following services have recovered and are operating normally:Azure Managed Grafana, Azure Database for MySQL Flexible Server, Azure Functions, Azure Database for PostgreSQL Flexible Server, Service Bus, Azure Storage, App Service (Web Apps), Azure Site Recovery, Backup (MAB), Azure Cosmos DB, Azure Resource Manager, Azure Data Explorer, Azure IoT Hub, Microsoft Defender for Cloud Apps, Azure Container Registry, Azure Policy, Azure NetApp Files, Azure Resource Graph, Azure Data Factory, Azure Databricks, Azure Cache for Redis, and Azure Synapse Analytics.Current Status: A severe weather event, including multiple lightning strikes, affected several datacenter facilities in the West US 2 region, resulting in concurrent utility power interruptions across multiple availability zones. Backup generators activated as designed; however, during the transition to sustained generator operation, a subset of generator systems were unable to fully synchronize under the sudden facility load, while others subsequently shut down due to thermal protection mechanisms as cooling systems were impacted by the broader power disruption. Because these events occurred across multiple facilities within the same timeframe, the resulting conditions exceeded the resiliency designed for this particular failure scenario.Datacenter utility power has been fully restored. HVAC systems have normalized, ambient temperatures have returned to expected operating ranges, and the majority of network and storage infrastructure has recovered successfully. While most services have returned to normal operation, two storage stamps are completing final recovery and validation activities. These stamps have shown consistent improvement throughout the recovery process, with functionality progressively returning to expected levels. The remaining impacted services should continue recovering incrementally as validation activities complete; we are monitoring stamp health to confirm sustained stability before declaring full mitigation.Estimated Time to Resolution: With datacenter power restored and the majority of network and storage infrastructure recovered, remaining work is focused on two storage stamps completing final recovery and data integrity validation activities. Based on current progress, we estimate full-service restoration within approximately 1-2 hours. Individual services dependent on these stamps will recover progressively as validation activities are completed.Customer Guidance:Single-region workloads will recover automatically as infrastructure restoration activities are completed; no customer action is required.We recommend postponing new deployments into West US 2 until this incident is resolved and using alternate regions for urgent deployment needs.Logical availability zones assigned to customer subscriptions may map to different physical availability zones. Customers can use the Locations API to understand this mapping: https://learn.microsoft.com/rest/api/resources/subscriptions/list-locations?HTTP#availabilityzonemappings.Next Update: We will provide our next status update within 60 minutes, or sooner if significant progress is made.

Impact: From 08:40 UTC, 27 May 2026, some customers using Azure Synapse Analytics (private link) may experience delays or failures accessing Synapse Studio or workspaces across multiple regions. As of now mitigation is in progress, and we are seeing initial signs of recovery.

Impact: From 08:40 UTC, 27 May 2026, some customers using Azure Synapse Analytics (private link, East US) may experience delays or failures accessing Synapse Studio or workspaces. We detected elevated connection failures via automated monitoring and are actively investigating.