Performing a Virtual Machine Upgrade from Windows Server 2008 to 2012


With the end of support for Windows Server 2008, it has become necessary for organizations to migrate out of this operating system. However, this can be time consuming and problematic for IT departments. This is where the upgrade is a benefit.

For many years, the idea of ​​upgrading from a version of the Windows server to a newer version was avoided. Not only could they be problematic and unreliable, the idea of ​​extracting all that “old” configuration data via an upgrade was undesirable. In fact, at the time of this writing, there are still organizations running Windows NT 4.0 and Windows 98.

While this was not a big concern, with the expansion of the cloud and more and more remote workers, the idea that all of those old operating systems are safe behind an environment secured by a perimeter wall. fire is no longer true. Therefore, it is essential that you have the security updates provided by Microsoft available and that you can install them. It also appears that Microsoft has improved its update process, which appears to be more reliable and stable than previous versions. However, as always, some types of systems NEVER need to be upgraded, such as domain controllers, Exchange servers, and SQL servers. Always check if the running services support the upgrade.

The process described below has been tested and performed several times in a production environment. I developed this process to speed up the transition from unsupported Windows Server 2008 to supported Windows Server 2012 R2. It also provides a way to easily “roll back” to Windows Server 2008 if something goes wrong.


1. The upgrade will create a folder for restore. Based on the tests, this folder will be approximately 35 to 40 GB. Verify that the appropriate free space exists. Otherwise, in Disk Management, add additional space before creating a virtual machine snapshot.

2. In vCenter, take a snapshot of the virtual machine. Give it an appropriate name, such as “Before 2012 upgrade”.

3. In vCenter, modify the hardware settings of the virtual machine by mounting the Windows Server 2012 ISO in the CD drive. Make sure the “connected” box is checked on the CD / DVD drive.

4. Once mounted, connect to the VM CONSOLE, do not use RDP. Go to the CD / DVD drive and launch the installer. Once at the prompt, select “Install Now”.

5. Since these systems are updated regularly, select “No thanks” on the updates screen.

6. For the operating system version, be sure to select “Windows Server 2012 R2 Standard (Server with a GUI).

7. Accept the terms of the license.

8. Select the “Upgrade” option on the Windows installation screen

9. The system will then run a compatibility report which will inform you if this is recommended. You can choose to ignore the report. It may say that an upgrade is NOT recommended.
10. If you continue with the upgrade, then the process will begin. It will take about 20-30 minutes to complete. During this time, the system may restart several times. It is best not to monitor it until the process is complete.
11. When the upgrade is complete, log into the system on the console.
12. For the virtual machine to function properly, VMware Tools may need to be upgraded if they are not up to date.
13. If necessary, vCenter will display a message similar to this one.

14. Click “Upgrade VMware Tools” on the right side, then from the console, upgrade the tools and restart the system.
15. Reconnect, verify connectivity by successfully pinging another IP address on the network, such as Gateway.
16. Start testing the applications to make sure the system is operating normally. Do NOT install Windows updates yet!
17. If all tests pass, the restore folder will be deleted. Since there is a snapshot of the virtual machine, this will be the restore point. Therefore, the folder is not needed and the space can be reclaimed. To do this, in Server Manager, navigate to “Add Roles and Features” and click Next until the Features option is listed. Expand “User Interfaces and Infrastructure”. Check the box next to “Office experience”. This will add the Disk Cleanup feature to the operating system. Keep clicking Next until you are finished, and then click Finish. Wait for the feature to be installed. The system will then require a restart.

18. Once installed, the properties of drive C: will now contain the option to run “Disk Cleanup”. Select this option to start the process.

19. The system will begin its calculations. In the list of items that can be removed to free up space, you will see a checkbox labeled “Previous Windows installations.” Check this box, then continue.

20. When the process is complete, perform Windows Updates. It will take several hours. Since this is a different operating system, there will be well over 100 updates to install for the system.
21. After the updates are complete, put the system into production for about a week to make sure it is functioning properly.
22. After the system has been online as Windows Server 2012 R2 for a sufficient period of time to determine that it is stable and functioning as expected, delete the snapshot.

23. The upgrade is now complete.


While upgrading Windows from an old operating system to a new one is not always ideal, there are situations where it can be done successfully. Each system should be analyzed independently to determine whether upgrading the system is better than rebuilding on a newer operating system. At least with the upgrade, the system will now be able to continue to receive monthly security updates from Microsoft. In today’s landscape, being able to receive and install security updates is crucial to securing a network.

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