Before going further, would you please let me know the detailed OS version? Is it Windows Server 2012 or Windows Server 2012Essentials? If you want to do an in-place upgrade from Windows Server 2012 Essentials to Windows Server 2012 Essentials R2,
please understand that it is not supported for this product. I suggest we could refer to the following similar thread.
server 2012 essentials upgrade to server 2012 essentials R2