blocked from unmanaged-to-managed disk migration by a stuck failed extension state.

Hi James Bozinopoulos

Thank you for contacting us about the blocked from unmanaged-to-managed disk migration issue. We have begun looking into it and will share our suggestions with you as soon as possible. If you have any additional details or concerns in the meantime, please let us know. We appreciate your patience while we work on this.

Hi James Bozinopoulos

The virtual machine and its data disks are using unmanaged disk storage, which requires manual conversion. Unmanaged disks store VHD files directly in a storage account and do not benefit from the Azure-managed disk platform features. A conversion step or wizard is required to create Managed Disks from those VHDs and reattach them to the VM.

Steps.

1. Stop the virtual machine. In the Azure portal, navigate to Virtual Machines > select your VM > click Stop.
2. Azure CLI

      az vm deallocate \
      --resource-group MyResourceGroup \
      --name MyVmName
   

3. Convert all disks on the VM to managed disks (OS and data)
   • In the VM’s page, select Disks from the left menu.
   • Click Migrate to managed disks.
   • Review the summary, ensure that all attached disks are listed, and click Migrate.
   • Wait for the conversion operation to complete (monitor notifications).
4. For each unmanaged disk VHD, run:

      
      az disk create \
      --resource-group MyResourceGroup \
      --name NewManagedDiskName \
      --source https://{storageAccount}.blob.core.windows.net/vhds/{vmName}-{diskType}.vhd \
      --os-type 
   

5. Then update the VM to use the new managed disks:

az vm update \
  --resource-group MyResourceGroup \
  --name MyVmName \
  --os-disk NewManagedDiskName    # for OS disk replacement

az vm disk detach \
  --resource-group MyResourceGroup \
  --vm-name MyVmName \
  --name OldDataDiskName

az vm disk attach \
  --resource-group MyResourceGroup \
  --vm-name MyVmName \
  --disk NewDataManagedDiskName

Start the virtual machine

Azure Portal

• Navigate back to your VM and click Start.
  • Start the virtual machine

Azure Portal

• Navigate back to your VM and click Start.
• CLi

az vm start \
  --resource-group MyResourceGroup \
  --name MyVmName

Verify migration

• In the portal, go to VM > Disks. Confirm that all disks are marked as “Managed”.
• Using CLI:

    az vm show \
      --resource-group MyResourceGroup \
      --name MyVmName \
      --query "storageProfile.osDisk.managedDisk.id"
  

Clean up old VHD blobs

• If you no longer need the unmanaged blobs, delete them from the storage account to avoid storage charges.
• Managed disks provide better reliability, simplified snapshots, and no storage account limits.
• Consider taking a snapshot or backup of your disks before conversion.

Thanks,
Manish

Hi James Bozinopoulos

I wanted to check if my last response made sense. I’d be glad to assist further or explain anything in more detail.