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Hyper-V Gen1 to Gen2 Upgrade: Step-by-Step Guide

Hyper-V offers two generations of virtual machines (VMs): Gen1 and Gen2. Gen1 VMs use traditional BIOS, while Gen2 VMs use UEFI, providing advanced features and better performance. Many businesses want to upgrade their existing Gen1 VMs to Gen2 to benefit from the advantages of UEFI-based VMs. In this blog post, we explain how to upgrade a Hyper-V Gen1 VM to a Gen2 VM.

Differences Between Gen1 and Gen2 VMs

Gen1 VMs (BIOS):

  • Use a traditional BIOS.
  • Support older operating systems and software.
  • Limited features compared to Gen2.

Gen2 VMs (UEFI):

  • Use UEFI instead of BIOS.
  • Support Secure Boot and other security features.
  • Better performance and modern features.
  • Require a 64-bit operating system that supports UEFI.

Prerequisites for the Upgrade

Before starting the upgrade, ensure the following prerequisites are met:

  • The VM’s operating system must support UEFI.
  • A complete backup of the VM is available.
  • Enough free storage space for the conversion.

Steps to Upgrade from Gen1 to Gen2

A direct switch from Gen1 to Gen2 is not possible in Hyper-V. Instead, you need to create a new Gen2 VM and migrate the data. Here are the steps in detail:

Step 1: Backup the VM

Ensure you have a complete backup of the current Gen1 VM. This can be done by exporting the VM in Hyper-V Manager:

  1. Right-click on the Gen1 VM.
  2. Select “Export”.
  3. Choose a location and confirm the export.

Step 2: Prepare the System

Perform all updates and necessary preparations on the Gen1 VM:

  1. Remove any software that might cause issues during migration.
  2. Perform a disk cleanup.

Step 3: Convert the VHDX File

The virtual hard drive (VHDX file) needs to be prepared for use in a Gen2 VM:

  1. Download a tool like Disk2vhd.
  2. Run Disk2vhd on the Gen1 VM and create a VHDX file of the system partition.

Step 4: Create Gen2 VM

Create a new Gen2 VM in Hyper-V Manager:

  1. Click on “New” > “Virtual Machine”.
  2. Select “Generation 2”.
  3. Configure the VM with the desired settings (CPU, RAM, network).

Step 5: Attach VHDX File

Attach the converted VHDX file to the new Gen2 VM:

  1. Open the settings of the new Gen2 VM.
  2. Navigate to “SCSI Controller” and select “Add Hard Drive”.
  3. Select the previously created VHDX file.

Step 6: Start and Verify the VM

Start the new Gen2 VM:

  1. Ensure the VM boots correctly and the operating system functions as expected.
  2. Check all services and applications.

Post-Upgrade Tasks and Optimizations

After successfully starting the Gen2 VM, further optimizations can be made:

  • Update drivers: Ensure all drivers are up-to-date.
  • Utilize UEFI features: Enable Secure Boot and other UEFI-specific features.
  • Optimize performance: Review and optimize VM settings for optimal performance.


Upgrading a Hyper-V Gen1 VM to a Gen2 VM offers numerous benefits, including better performance and enhanced security features. By carefully planning and following the steps described above, you can successfully carry out this process and modernize your IT infrastructure.

Are you not yet using Hyper-V or need a team of experts by your side? Contact us now and schedule a free and non-binding initial consultation.

If you want to learn more about our offer for migrating from VMware to Hyper-V, click HERE to go to the respective page.

Ready to migrate from VMware to Hyper-V or ccloud³?

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