Windows Migration¶

Migrating Windows workloads from VMware vCenter to HVM Clusters is fully supported with automated VirtIO driver injection. The migration system handles driver installation and disk bus conversion automatically in most cases.

Automated Driver Injection¶

When a Windows VM is included in a Migration Plan, the system automatically:

1. Installs VirtIO guest tools on the source VM during the Prepare phase (via network download of the MSI package)

2. If network installation fails, falls back to ISO-based installation — the VirtIO ISO is uploaded to the VMware datastore, mounted to the VM, and drivers are installed via msiexec

3. Creates the target VM with temporary SATA disks so Windows can boot without VirtIO drivers

4. Adds a small VirtIO helper disk that triggers Windows to detect and load VirtIO drivers from the driver store

5. Boots the target VM and waits for Windows to register the VirtIO drivers (up to 10 minutes)

6. Shuts down and switches all disks to VirtIO bus — SCSI disks map to VirtIO-SCSI, IDE/SATA disks map to VirtIO Block

7. Removes the helper disk and ISO volumes, then starts the final VM

This entire process is handled by the Reconfigure phase and requires no manual intervention for supported Windows versions.

Supported Windows Versions¶

• Windows Server 2016

• Windows Server 2019

• Windows Server 2022

• Windows Server 2025

• Windows 10

• Windows 11

Manual Preparation (Fallback)¶

In rare cases where automated driver injection fails (e.g., restricted network access and no VirtIO ISO available in vCenter), you may need to manually prepare the Windows VM before migration. The steps below cover manual VirtIO driver injection for a Windows VM running on vCenter.

Prerequisites for manual preparation:

• The VM is configured with EFI or BIOS boot

• The VM has access to the recovery partition (or Windows Recovery Environment media)

• The VirtIO drivers ISO is available

Step 1: Boot into Windows Recovery Environment

Restart the VM into Windows RE. Select a keyboard layout if prompted, then choose Troubleshoot ‣ Command Prompt.

Step 2: Load storage drivers (if disks not visible)

In the Command Prompt, check disk visibility:

diskpart
list disk

If no disks appear, mount VMware Tools from vCenter (Actions ‣ Guest OS ‣ Install VMware Tools…), then load the storage driver:

list volume

Note the CD-ROM drive letter (e.g., “D”), then:

drvload "D:\Program Files\VMware\VMware Tools\Drivers\pvscsi\Win10\amd64\pvscsi.inf"

Verify disks are now visible:

diskpart
list disk

Assign drive letters if needed:

list volume
select volume 1
assign letter=c
exit

Unmount VMware Tools from vCenter when done.

Step 3: Inject VirtIO drivers

Upload the VirtIO ISO to a vCenter datastore or Content Library. Mount it to the VM via a CD-ROM device. Then inject the storage drivers:

dism /image:C:\ /add-driver:D:\viostor\2k22\amd64\viostor.inf

dism /image:C:\ /add-driver:D:\vioscsi\2k22\amd64\vioscsi.inf

Close Command Prompt and click Continue to boot Windows normally.

Step 4: Install VirtIO guest tools

Once logged back into Windows, navigate to the mounted VirtIO ISO and install:

• virtio-win-gt-x64.msi

• virtio-win-guest-tools.exe

Keep all default selections. After installation, unmount any ISOs attached to the VM.

Step 5: Power down and migrate

Shut down the VM and ensure it stays powered off (note that the VMware Cloud integration may have “AUTOMATICALLY POWER ON VMS” enabled — if so, shut down from the product UI or temporarily disable that setting). The VM is now ready to be included in a Migration Plan.

Post-Migration: VMware Tools Cleanup¶

After migration, VMware Tools remains installed but is non-functional on HVM. To prevent startup errors:

• Navigate to Settings ‣ Apps ‣ Startup in the Windows guest and disable VMware Tools Core Service

• Optionally, fully uninstall VMware Tools using Microsoft’s program removal troubleshooter