Microsoft’s New VM Conversion Tool: Migrate VMware VMs to Hyper-V using Changed block tracking (CBT)

Microsoft has just dropped a shiny new tool that promises to make your life easier when moving workloads from VMware to Hyper-V. The VM Conversion tool, now available in public preview as an extension in Windows Admin Center (WAC), is designed to streamline the migration of VMware virtual machines (VMs) to Hyper-V with minimal fuss, no extra cost, and most importantly – minimal downtime.

If you’ve ever wrestled with third-party tools, custom PowerShell scripts, or complex appliances to pull off a VMware-to-Hyper-V migration, this tool might just be the game-changer you’ve been waiting for. Let’s dive into what this tool is all about, how it works, and why it’s worth a look for your next migration project.

Why Migrate from VMware to Hyper-V?

Before we get into the nitty-gritty, let’s address the elephant in the room: why would you want to migrate from VMware to Hyper-V in the first place? VMware’s vSphere and ESXi are rock-solid platforms, but recent Broadcom licensing policy and packaging is very disappointing. On the other hand, Hyper-V has been catching up as don’t forget, it is a core Microsoft Azure technology.

For organizations already deep in the Microsoft ecosystem, Hyper-V offers seamless integration with Windows Server, System Center, and Azure. Plus, let’s not forget the cost factor – Hyper-V comes bundled with Windows Server licenses, which can save you a pretty penny compared to VMware’s licensing model where you pay the bundle with software which probably won’t be used within your organization. Add to that Hyper-V’s robust features like Shielded VMs, live migration, and hybrid cloud capabilities, and it’s no wonder some IT teams are eyeing a switch.

Screenshot from Microsoft outlining the architecture

But migrations are never a walk in the park. Converting VMs between hypervisors is like trying to convince a cat to take a bath – possible, but it requires patience, the right tools, and a bit of luck. Historically, VMware-to-Hyper-V migrations meant leaning on third-party tools like StarWind V2V Converter or Microsoft’s now-retired Virtual Machine Converter (MVMC), or even manually exporting and importing VMs using OVF files. These methods worked, but they often involved complex setups, downtime, or extra costs. Enter Microsoft’s VM Conversion tool in Windows Admin Center, which aims to simplify the process with an agentless, appliance-free approach. Let’s break it down.

What Is the VM Conversion Tool?

The VM Conversion tool is a new extension in Windows Admin Center (WAC) v2, released in public preview on August 20, 2025. It’s designed to migrate VMware VMs from vCenter or ESXi to Hyper-V with minimal downtime, supporting both Windows and Linux guest operating systems. Unlike older tools like MVMC, which required separate installations and sometimes clunky workflows, this tool is integrated directly into WAC’s browser-based interface, making it accessible and easy to use for admins of all sizes—from small businesses to enterprise IT teams.

The tool leverages VMware’s Change Block Tracking (CBT) for efficient data replication, ensuring that your VMs stay online during most of the migration process. It supports bulk migrations (up to 10 VMs at a time), preserves critical configurations like static IPs and boot settings, and handles multi-disk VMs without breaking a sweat. Oh, and did I mention it’s free? No hidden fees, no extra appliances, just a lightweight extension that gets the job done.

Key Features of the VM Conversion Tool

So, what makes this tool stand out? Here’s a rundown of its key features, based on Microsoft’s documentation and my own take on why they matter:

• Minimal Downtime with CBT: The tool uses a two-phase replication process. First, it performs an initial sync while the source VM is still running, copying most of the data. Then, with your approval, it powers down the source VM for a final delta sync to capture any changes. This approach keeps downtime to a minimum—think seconds or minutes, not hours. Perfect for those mission-critical workloads that can’t afford to be offline.
• Bulk Migration: You can migrate up to 10 VMs at once, grouping them by application dependencies, cluster requirements, or business needs. This is a lifesaver for admins managing large environments where one-by-one migrations would be a nightmare.
• Boot Configuration Mapping: The tool automatically maps BIOS-based VMs to Hyper-V Generation 1 and UEFI-based VMs to Generation 2, ensuring compatibility without manual tweaking. No more late-night PowerShell sessions to fix boot issues!
• OS Agnostic: Whether your VMs are running Windows Server (2012 R2 to 2025) or Linux distributions like Ubuntu, Debian, or Red Hat, the tool adapts. Just make sure to install Hyper-V Integration Services (v4.3 or later) on Linux guests before migration to avoid boot headaches.
• Agentless and Appliance-Free: No need to install guest agents or deploy separate conversion appliances. The tool runs directly on the WAC gateway, using VMware’s Virtual Disk Development Kit (VDDK) and PowerCLI to talk to vCenter/ESXi.
• Prechecks for Peace of Mind: Before migration, the tool runs comprehensive prechecks on disk types, boot configurations, memory, and more. If something’s off (like an active snapshot), it’ll let you know so you can fix it before proceeding.

Getting Started: Setup and Prerequisites

Ready to give it a spin? Setting up the VM Conversion tool is straightforward, but there are a few prerequisites to check off first. Here’s what you’ll need, per Microsoft’s guidelines:

• Windows Admin Center v2 (GA): Ensure you’re running the latest version (build 2410 or higher) on your gateway server.
• Hyper-V Role: The destination host(s) must have the Hyper-V role enabled.
• VMware PowerCLI: Install it on the WAC gateway using the PowerShell command: Install-Module -Name VMware.PowerCLI.
• VMware VDDK 8.0.3: Download and extract the Virtual Disk Development Kit to C:\Program Files\WindowsAdminCenter\Service\VDDK.
• Microsoft Visual C++ Redistributable: Install the 2013 version (and any older runtimes if required) on the WAC gateway.
• vCenter 6.x or 7.x: The tool supports VMware vCenter versions 6.x and 7.x. Keep your vCenter credentials handy for the connection setup. That’s pretty shame that they did not include vSphere 8.x support, but hey, it might come in the GA release.
• No Snapshots: VMs with active snapshots will fail the precheck, so consolidate or delete them before starting.
• Linux Prep: For Linux VMs, install Hyper-V Integration Services v4.3 to ensure they boot properly post-migration.

To install the extension, open WAC, head to Settings > Extensions, search for “VM Conversion (Preview),” and click Install. Once it’s set up, you’ll find the VM Conversion tool under the Extensions menu in WAC.

The Migration Workflow

Here’s a step-by-step look at how the migration process works:

1. Connect to vCenter: In WAC, navigate to the VM Conversion extension and enter your vCenter credentials to discover your VMware VMs.
2. Select VMs: Choose up to 10 VMs to migrate. You can group them based on dependencies (e.g., VMs in the same application stack).
3. Run Prechecks: The tool validates disk types, boot settings, and other configurations. Fix any issues flagged during this step.
4. Initial Sync: The tool uses CBT to replicate the VM data to the Hyper-V host while the source VM remains online.
5. Final Delta Sync: After you approve, the source VM is powered down, and a final sync captures any changes since the initial replication.
6. Post-Migration Cleanup: VMware Tools aren’t automatically removed (except for Windows VMs in some cases), so you may need to uninstall them manually. For Linux VMs, verify that Hyper-V Integration Services are installed and working.

After migration, check network settings, DNS configurations, and BIOS GUIDs (which may need manual updating via the provided Update-VMBiosInfo.ps1 script if licensing or identity sync is an issue).

You can also convert dynamic VHDX disks to fixed-size disks for better performance using PowerShell: Convert-VHD -Path “C:\VMs\MyDisk.vhdx” -DestinationPath “C:\VMs\MyDisk_Fixed.vhdx” -VHDType Fixed.

Microsoft WAC with VM Conversion extension installed

Limitations and Gotchas

No tool is perfect, especially in public preview. Here are a few things to watch out for:

• No vSAN Support: VMs running on VMware’s virtual SAN (vSAN) aren’t supported. You’ll need to move them to standard storage first.
• No Azure Local: This tool is for on-premises Hyper-V migrations only. For Azure, use Azure Migrate instead.
• Static Memory: Migrated VMs are configured with static memory, even if the source used dynamic memory. You can re-enable dynamic memory post-migration in WAC.
• Manual Cleanup: VMware Tools may linger on migrated VMs, so budget time for cleanup, especially for Linux guests.
• Preview Caveats: As a preview release, expect some rough edges. Test thoroughly in a non-production environment before migrating critical workloads.

Why This Matters

The VM Conversion tool fills a long-standing gap in Microsoft’s virtualization portfolio. For years, admins relied on third-party tools or System Center Virtual Machine Manager (SCVMM) for VMware-to-Hyper-V migrations, which could be overkill for smaller setups.

This new tool brings a lightweight, GUI-driven alternative that’s perfect for small to medium-sized businesses or teams consolidating on-premises infrastructure. It’s also a strategic move by Microsoft to lure VMware customers, especially with Azure Arc integration planned for future releases, paving the way for hybrid cloud scenarios.

Final Words

Microsoft’s VM Conversion tool in Windows Admin Center is a promising addition for anyone looking to migrate VMware VMs to Hyper-V without breaking the bank or their sanity. Its agentless design, minimal downtime, and integration with WAC make it a compelling option for IT admins, whether you’re running a small shop or a sprawling data center. Just be sure to test it thoroughly as it is a public preview only, prep your Linux VMs, and keep an eye on those post-migration cleanups.

If you’re planning a migration, check out the full documentation on Microsoft Learn and the Microsoft Community Hub for more details. Happy migrating!

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