CUSI Service Disruption Notice: Virtual Desktop Infrastructure (VDI) – Azure East US

Incident

CUSI Service Disruption Notice: Virtual Desktop Infrastructure (VDI) – Azure East US

Status: Closed
Start:
End:
Duration: 2 days 20 hours 11 minutes
Affected Components:
CUSI Cloud Hosting UMS
Affected Groups:
CUSI
Investigating

Issue Summary

We are currently experiencing a service disruption impacting access to Virtual Desktop Infrastructure (VDI) environments hosted in the Azure East US region. Users may be unable to connect to their virtual desktops, or experience authentication failures and connection timeouts when attempting to start new or existing sessions.

Impact

  • Services Affected: Azure‑hosted Virtual Desktop Infrastructure (VDI)
  • Users Impacted: End users with VDIs hosted in Azure East US
  • Symptoms:
    • Inability to establish new VDI sessions
    • Existing session connections failing or timing out
    • Intermittent connectivity to virtual desktops

Root Cause

Microsoft has confirmed an active, multi‑service Azure platform incident in the East US region.

According to Microsoft:

“Starting at 11:39 UTC on 24 April 2026, a subset of customers with resources in the East US region may experience failures or delays when provisioning, scaling, or updating Azure resources. This issue initially affected one availability zone; however, as traffic was automatically rerouted and shared services were involved, customers in other availability zones may also experience impact. Existing workloads may have intermittent connectivity issues, including access to Virtual Machines and Virtual Desktop sessions.”

Initial investigation indicates this is an Azure regional dependency issue. No customer‑side configuration changes have been identified as contributing factors.

Actions Taken

  • Incident declared and escalated to Microsoft Azure support
  • Health checks completed on VDI hosts and associated networking components
  • System logs and performance metrics reviewed
  • Ongoing monitoring of Azure East US regional health

Workaround

At this time, there is no reliable workaround for users requiring access to VDIs hosted in the Azure East US region.

Current Status

Our team is actively monitoring the situation and working closely with Microsoft Azure toward full service restoration. We will continue to provide updates as more information becomes available or as service status changes.

More Information

For the latest updates, please monitor:

We sincerely apologize for the disruption and appreciate your patience while we work to restore full service.

Resolved

Summary

The previously reported service disruption impacting Virtual Desktop Infrastructure (VDI) environments hosted in Azure East US has been resolved. Microsoft has confirmed full service restoration across all availability zones.

Root Cause

A faulty deployment to a regional Azure control plane backend service introduced a regression that caused provisioning, scaling, and update operations to fail. The issue initially surfaced in one availability zone and spread to the remaining two as Microsoft's rollback progressed. Microsoft resolved the incident by rolling back all three availability zones to the last known good state.

Resolution Timeline

  • 11:39 UTC, 24 Apr – Customer impact began
  • 11:59 UTC, 24 Apr – Microsoft detected the issue and began investigation
  • 14:30–14:40 UTC, 24 Apr – Root cause identified; rollback initiated across affected zones
  • 19:02–23:22 UTC, 24 Apr – Rollback completed across all three availability zones
  • 00:15 UTC, 25 Apr – Full service restoration confirmed; incident closed

Next Steps

Microsoft will publish a Preliminary Post Incident Review (PIR) within approximately 72 hours, followed by a Final Post Incident Review within 14 days. Our team will review findings once available and continue monitoring the environment.

Resources

CUSI apologizes for the disruption and thank you for your patience.

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