How do I upgrade Hyper-V Server 2019 to Windows Server 2025 without a clean install?

Can you perform an in-place upgrade from Hyper-V Server 2019 to Windows Server Standard?

Many administrators still rely on Hyper-V Server 2019. This free virtualization solution offered enterprise-grade capabilities without the overhead of a full graphical interface. However, Microsoft discontinued this specific free product line in 2022. While the Hyper-V role persists in modern Windows Server versions, the standalone Hyper-V Server SKU does not.

Officially, Microsoft states that upgrading from Hyper-V Server 2019 to Windows Server 2022 or 2025 requires a clean installation. This creates a significant burden. You must back up virtual machines, wipe the host, install the new OS, and restore data. This process incurs downtime and configuration loss. However, the community has identified a functional, albeit unsupported, method to force an in-place upgrade.

Understanding the Technical Limitations

Hyper-V Server 2019 contains only the Windows hypervisor, a restricted driver model, and virtualization components. It functions essentially as a “Server Core” installation locked to a specific role. The installer for Windows Server 2025 Standard checks the current edition before proceeding. When it detects “Hyper-V Server,” it blocks the upgrade path because the editions do not match.

To bypass this, you must modify the system registry to trick the installer. By altering the reported Edition ID and Installation Type, the Windows Server 2025 setup routine perceives the host as a standard Windows Server installation rather than the specialized Hyper-V SKU.

The Registry Modification Procedure

This process carries risk. You should perform a full backup of the host and all virtual machines before proceeding. The goal is to mask the current operating system identity.

Step 1: Preparation

Access the command line or PowerShell on your Hyper-V Server. Launch regedit.exe. Navigate to the following path:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion

Step 2: Modify Identifiers

You must change three specific string values to match a standard server installation. Locate and edit the following keys:

• CompositionEditionID: Change from ServerHyper to ServerStandard
• EditionID: Change from ServerHyper to ServerStandard
• InstallationType: Change from Server Core to Server

Step 3: Regional Settings (Optional)

Some users report success without this step, but consistency helps. Ensure your system locale matches the installation media (usually en-US). You can adjust this via intl.cpl.

Executing the In-Place Upgrade

Once the registry reflects a “Standard” edition, mount your Windows Server 2025 ISO. Run setup.exe.

The installer will now detect a compatible upgrade path. It allows you to select “Keep personal files and apps.” This preserves your Hyper-V configurations, virtual switch settings, and stored VM files. The installation proceeds as a typical Windows Server upgrade. Upon reboot, the OS migrates the existing roles to the new Windows Server 2025 environment.

Critical Advisory on Licensing and Support

While this method works technically, it alters the licensing landscape of your infrastructure.

Licensing Compliance

You are moving from a free product to a paid product. You must possess a valid Windows Server 2025 Standard license. Ensure you activate the new OS immediately after the upgrade completes to remain compliant.

Support Status

Microsoft does not officially support this upgrade path. If the host encounters kernel-level instability or driver conflicts later, official support channels may require a clean reinstall to troubleshoot.

Best Use Case

Use this method primarily for standalone virtualization hosts. If the server runs other roles or third-party agents, the risk of configuration corruption increases.

Cross-Platform Migration Possibilities

This registry manipulation technique highlights the underlying architectural similarities between Windows editions. Similar methods allow converting a client OS (like Windows 10 or 11 Enterprise) into a Server OS. However, migrating a workstation to a server usually results in the loss of client-specific features and should only be utilized in lab environments or desperate recovery scenarios.

For production environments, this Hyper-V upgrade hack serves as a powerful bridge to modernize infrastructure without the extended downtime of a bare-metal rebuild.