AB#7213: slow-vm-start-extensions-troubleshooting.md

Author: amsliu

support/azure/virtual-machines/windows/media/slow-vm-start-extensions-troubleshooting/agent-status-version.png

@@ -0,0 +1,78 @@
+---
+title: Slow Azure Virtual Machine Start operations caused by extensions being in a failed state
+description: Troubleshooting guide for slow Azure Virtual Machine Start operations caused by the extensions being in a failed state.
+ms.date: 08/28/2025
+ms.reviewer: v-liuamson; v-gsitser
+ms.service: azure-virtual-machines
+ms.collection: windows
+ms.custom: sap:Cannot start or stop my VM
+---
+# Slow Azure Virtual Machine Start operations caused by extensions being in a failed state
+
+## Overview
+
+You may experience slow Azure Virtual Machine (VM) **Start** or **Redeploy**
+operations when one or more of the VM extensions are in a **Failed** state.
+This article will cover possible causes and resolutions.
+
+## Symptom
+
+In this scenario, the VM's guest OS can be active and working and the
+VM can connect successfully, but the operation is still appearing to run
+in the Azure portal.
+
+## Cause
+
+VM extensions are software components that run inside the VM to enable
+configuration management, security, monitoring, and other features. VM
+extensions have a 90-minute provisioning timeout, which means they must
+complete their installation or update within that time limit. If an
+extension fails to provision within the timeout, it will be marked as
+failed and will not be retried until the next VM operation that triggers
+the extension, such as a **Start** or a **Redeploy**.
+
+When a VM has one or more extensions in a failed state, it can cause
+delays in other VM operations, such as **Start** or **Redeploy** because the Azure
+platform will try to provision the failed extensions again before
+completing the operation. This can result in the VMs showing a **Starting**
+status for an extended period.
+
+## Resolution
+
+To mitigate this issue, you may follow these steps:
+
+1. Review the extension status and logs for the VM to determine the
+    root cause of the failure.
+
+    - To check the status of the extensions installed on the VM, go to the
+      VM Blade and select the **extensions + applications** option under
+      **Settings** in the left-hand pane. If the status is not **Provisioning Succeeded**, the extension may need to be removed or further investigation may be required.
+
+      :::image type="content" source="media/slow-vm-start-extensions-troubleshooting/extensions-applications-status.png" alt-text="Screenshot of the portal with the extenstions and applications statuses. Status is highlighted.":::
+
+    - Logs for the extensions can be found within the Guest OS of the VM.
+      See the [Further Troubleshooting section](#further-troubleshooting) for more information.
+
+1. Check the status of the VM "Guest Agent", as it is responsible for
+    handling the provisioning of extensions. If the "Guest Agent" is not
+    in a ready state, it may need to be reviewed. For further guidance,
+    refer to the documents mentioned in the [Further Troubleshooting section](#further-troubleshooting).
+
+      :::image type="content" source="media/slow-vm-start-extensions-troubleshooting/agent-status-version.png" alt-text="Screenshot of the portal with the VM overview. Agent status and Agent version are highlighted.":::
+
+1. Resolve the extension failure by either fixing the configuration or
+    uninstalling the extension. You can use the Azure portal, PowerShell, CLI, or REST API to update or remove the extension. You may need to contact the extension publisher for support if the issue is related to the extension functionality or compatibility.
+
+1. Stop then Start the VM to verify that the extension provisioning
+    succeeds and the VM Start operation completes faster. You can use
+    the Azure portal, PowerShell, CLI, or REST API to "Stop/Start" the
+    VM.
+
+## Further Troubleshooting
+
+For more guidance on how to troubleshoot Azure VM guest agent and
+extension issues, see:
+
+- [Troubleshooting Windows VM extension failures](/azure/virtual-machines/extensions/troubleshoot)
+- [Troubleshoot Azure Windows VM Agent issues](/azure/virtual-machines/windows-azure-guest-agent)
+- [Troubleshoot the Azure Linux Agent](/azure/virtual-machines/linux-azure-guest-agent)

support/azure/virtual-machines/windows/media/slow-vm-start-extensions-troubleshooting/extensions-applications-status.png

@@ -381,6 +381,8 @@ items:
     href: restart-resize-error-troubleshooting.md
   - name: Restarting, shutting down, or stopping services
     href: boot-error-troubleshoot-windows.md
+  - name: Slow VM start caused by extensions troubleshooting
+    href: slow-vm-start-extensions-troubleshooting.md
 
 - name: VM restarts or stops unexpectedly
   items: