Upgrading guest OS in VMware vSphere ESXi VM from Windows Server 2012 R2, Windows Server 2016, Windows Server 2019, Windows Server 2022 to Windows Server 2025

Products

• VMware vSphere ESXi 7.0
• VMware vSphere ESXi 8.0
• VMware vSphere ESXi

Issue/Introduction

The in-place upgrade of the guest operating system (between major OS release versions, such as Windows Server 2012 R2, Windows Server 2016, Windows Server 2019 or Windows Server 2022 to Windows Server 2025) is not recommended. The best practice is to install a new major OS release in a new VMware vSphere ESXi VM.

Support Considerations

• Read the operating system vendor's documentation to ensure that the specific upgrade scenario and method is supported. For example, Overview of Windows Server upgrades | Microsoft Learn.
• If the OS vendor does not support a particular upgrade scenario, then VMware by Broadcom does not provide support for such scenarios due to lack of ability to collaborate with the OS vendor.
• In-place upgrade is a feature of the operating system. If you encounter problems, it is best to first contact the OS vendor for assistance. If the OS vendor has narrowed down the problem as specific to VMware by Broadcom software, then VMware by Broadcom can provide assistance.
• Some VMware by Broadcom products do not support in-place upgrade of the guest operating system in a VM. For more details, see VMware support for guest operating system upgrade (broadcom.com).
• Check the VMware Compatibility Guide - Guest/Host Search to ensure new operating system version is supported as guest OS on the VMware by Broadcom product.
• Check the configuration of VM to ensure that it meets requirements to run new OS release. New major OS releases sometime increase the minimum required amount of memory, video RAM, disk space, etc. In addition, performing OS upgrade consumes disk space, so ensure that the VM has adequate storage to complete the upgrade. It may be necessary to power off the VM to make some of these configurations before starting the upgrade.
• For all applications running in the guest OS, contact the application vendor to determine their support policies and guidance for conducting operating system upgrades.

Environment

VMware vSphere ESXi 7.0.3

VMware vSphere ESXi 8.0.x

Resolution

Note: Before upgrading the guest OS:

• Upgrade VMware Tools to the latest version available for current Windows release
• Take a snapshot of the VM or save backup of the VM and test the upgrade in a cloned VM.

  
If you have a Windows Server 2025 ISO image used for Windows Server 2025 installation, you can follow below procedure:

1. Mount this ISO file to the VM, select Virtual Machine -> Edit Settings -> CD/DVD drive -> Datastore ISO file, click Browse to select the Windows Server 2025 ISO file from datastore as CD/DVD media.
2. Logon to the guest OS and double-click CD-ROM from the File Explorer.
3. Follow the installation prompts to complete the OS upgrade.
4. Upgrade or reinstall VMware Tools after OS upgrade is done.
5. Shutdown the VM, select Virtual Machine -> Edit Settings -> VM Options -> General Options, change Guest OS Version to Microsoft Windows Server 2025 (64-bit) or Microsoft Windows Server 2022 (64-bit). For Windows Server 2025 guest OS option see, Installing Windows Server 2025 on a VMware Virtual Machine (broadcom.com)