We have completed moving all our vms from Azure to our own cloud environment. We moved the vms by creating full images of each of them.
Once the move was completed we were faced with a problem. All the vms in Azure run Windows 2012 R2 Datacenter. We don’t have any use for that OS version besides the licensing costs are much higher than the Standard.
That being the case we looked for the possibility of doing a downgrade by either using the install of Windows 2012 R2 Standard or even by changing the licensing key. The bad news is that officially Microsoft does not support the downgrade of the servers.
The only way to downgrade the server we were left with was to re-build the servers from scratch which was an impossible task for us.
Open the registry database by executing regedit.exe from the command prompt. Look for the key HKEY_LOCAL_MACHINE\SOFTWARE\Microsof\Windows Nt\CurrentVersion.
Now all you have to do is to run the install of Windows 2012 R2 Standard and select to upgrade. When the install asks if you would like to do an update just continue the install. Once the install completes you’ll have your OS downgraded to Windows Server 2012 R2 Standard. You can confirm it but checking the ProductName key.