Recently a client asked why their virtual SQL Server was only seeing 4 vCPU’s out of the 8 vCPU’s assigned to the virtual machine. After verifying the server was licensed with Windows Server Standard edition I explained the Standard edition limitations. Microsoft restricts Windows Server Standard edition to 4 CPU’s, or in the case of virtual machines 4 vCPU’s. The client asked if it was possible to change the server from Standard edition to Enterprise edition in order to support 8 vCPU’s without having to rebuild the server from scratch. The number of supported processors for each Windows Server 2008 R2 edition can be found here. Normally I don’t recommend 8 vCPU’s but it was a very I/O intensive SQL Server and one of the client’s most important servers. This article will walk through the process of changing Windows Server Standard edition to Enterprise edition, but the process can be used when upgrading any edition.

Before getting started there are a couple caveats to know when upgrading a Windows Server license edition.

1) The server’s license cannot be upgraded if the server is an Active Directory domain controller. The only way around this is to transfer the FSMO roles to another domain controller and then demote the domain controller

2) This process is irreversible so it is not possible to go back to an earlier license edition

In the instructions below I use the example of upgrading Server 2008 R2 Standard edition to Enterprise edition but this process can be used when upgrading any edition

• First reset the licensing back to the generic Microsoft KMS key for the version of Windows currently in use, Server 2008 R2 Standard in this case. The generic KMS keys provided by Microsoft can be found here

  From the Start Menu right-click Computer and select Properties. Towards the bottom of the System Properties dialog box look for Windows activation and select Change product key

• Input the generic KMS key retrieved for the current license edition and choose Next

• Once it finishes resetting to the generic KMS key a Windows Activation error,0XC004F074, will pop-up

• Notice the server is no longer activated by looking back at the System Properties dialog box

• Next find the generic KMS key for the license edition you want to upgrade to, Server 2008 R2 Enterprise in this case. Refer back to this link for the generic KMS keys
• From the command prompt run the following command:

DISM /online /Set-Edition:<edition ID> /ProductKey:XXXXX-XXXXX-XXXXX-XXXXX-XXXXX

• The following is used for Server 2008 R2 Enterprise:

DISM /online /Set-Edition:ServerEnterprise /ProductKey:XXXXX-XXXXX-XXXXX-XXXXX-XXXXX

• Once the command completes it will ask to reboot. Select Y to reboot. This sets the Server 2008 R2 edition to Enterprise but Windows still needs to be activated with a valid Enterprise license
• After the reboot open System Properties and select Change product key
• Now input a valid product key and select Next. If a valid product key is used the “Activation was successful” screen will be displayed!

Now that the server is set to Enterprise edition it is possible to add up to 8 vCPU’s!