Upgrading to Windows Server 2012 – Part 1

Things to consider before the upgrade

Hi Again everybody,

Windows Server 2012 was launched in August this year. With an innovative user interface, powerful remote management tools, a big bunch of new features, major enhancements to existing ones, and a focus towards cloud, this is perhaps the most significantly enhanced release of Windows Server operating system ever. This blog series will focus on things you need to consider while upgrading your existing Window Server 2008 or Windows Server 2008 R2 infrastructure to Windows Server 2012 and will discuss some of the top issues for which customers call Microsoft support.

SKU considerations:

When it comes to choosing the right SKU in earlier versions of Windows Servers, you had a lot to think about in terms of features that are available, number of processor and memory support. In Windows Server 2012, we have made it easier for you to make this decision. Windows Server 2012 comes in 4 SKUs:

Windows Server 2012 Datacenter and Windows Server 2012 Standard are the fully functional editions of Windows Server 2012. There is no difference between the two in terms of processor/memory support, features and functionality. What differentiates the two is the number of virtual machines you can run without paying for additional Windows licenses. The Datacenter edition is meant for virtualization and private cloud deployments and includes unlimited virtualization rights. The Standard edition is meant for application hosting on physical servers with minimized virtualization; hence, the Standard license will entitle you to run up to 2 virtual machines on up to 2 processors. For more information about licensing and price check this guide.

Windows Server 2012 Essentials is the next version of Windows Small Business Server (SBS). This is a powerful and flexible solution that is ideal for Small business. Some of the features are stripped down, and additional features that support a small business are added to this edition. To get more details about this product check this link.

Windows Server 2012 Foundation provides a general purpose server experience and has no virtualization right and is limited to 15 user accounts. This is available through OEM only.

Hardware Considerations:

To install Windows Server 2012 at minimum, you need a 1.4 GHz 64-bit processor, 512 MB of RAM, 32 GB of disk space, DVD Drive, Super VGA (800x600) or higher resolution monitor, keyboard and mouse. Depending on the mode you install (Server core or server with a GUI), the Windows installation typically takes anywhere from 8GB to 16 GB, however we always recommend that you keep 32Gigs of disk space or more, so that you have sufficient space for paging and servicing. There will also be additional requirements depending upon the roles and services that this server will host.

Upgrade Path Considerations:

There are upgrade paths to Windows Server 2012 from both Windows Server 2008 SP2 and Windows Server 2008 R2. The following table summarizes the available upgrade paths.

Upgrade Options

Windows Server 2012


Windows Server 2012


Windows 2008 Standard/Enterprise with SP2 (x64)



Windows 2008 Datacenter with SP2 (x64)



Windows Web Server 2008



Windows 2008 R2 Standard or Enterprise with Sp1



Windows 2008 R2 Datacenter with Sp1



Windows Web Server 2008 R2



The same old rules still apply. In-place upgrades from 32-bit edition of Windows Server 2008, upgrades from one language to another, from one build type to another (chk to fre) are not supported. You also cannot perform an in-place upgrade from any pre-RTM builds of Windows Server 2012 (like the Release Preview build) to the RTM build. Depending on the role you are running, an upgrade would be blocked from being performed. As an example, having Failover Clustering as an added role in Windows 2008 R2 will block an upgrade.

Installation Modes:

When you perform a Windows Server Installation by booting of the media, the setup will give you two modes of installing your Windows Server. You can either opt to install Windows in full server mode with the GUI, or in the Server Core mode without the GUI experience.


Server Core is what we recommend customers to move to since this requires fewer resources, has a smaller attack surface, and a smaller patch footprint. Since the Server Core does not have the Server Manager or any other MMCs to manage roles and features, management must be done either remotely from a client machine or through the command prompt or Powershell at the console.

Minimal User Interface:

In Windows Server 2012, we also introduce an intermediate mode of operation called the Minimal User Interface. Minimal User Interface is similar to server core as there is no Explorer. However, it lets you use the Server Manager and most of the management MMCs for roles and features on this machine without installing the explorer shell. This way, you can still use the management tools locally. This article discusses about the minimal user interface and how you can transition to this from the server core mode: http://blogs.technet.com/b/canitpro/archive/2012/10/02/from-server-core-to-gui-to-minshell.aspx

Other considerations:

If you have an existing Server Core for Windows Server 2008 with Service Pack 2 (SP2) or Windows Server 2008 R2 installation, you have to upgrade this to Windows Server 2012 Server Core. Once upgraded, you then have an option to install the GUI if required. Similarly, you must first upgrade full server installation of Windows Server 2008 and Windows Server 2008 R2 to Windows Server 2012 (Server with a GUI). After the upgrade is done, you can then remove the graphical shell as needed. The following KB article talks about a specific issue on the upgraded Windows Server 2012:

2775484 Unable to convert to Server with a GUI from Server Core on an upgraded Windows Server 2012-based machine

In earlier versions of Windows Servers, once you install the server in Core or with GUI mode, you could not switch to the other. The only option was to rebuild the server from scratch. In Windows Server 2012, we have changed the package hierarchy in such a way that you can choose to add or remove the GUI at any point of time. So you can actually install a full server, then configure it using the full blown UI. Once everything is done, you could just remove the graphical shell and convert your Windows Server to Server Core. Similarly, if you are running a Server 2012 Core machine, you can install the Graphical Shell, and management tools, to go back to the Full Server mode. The option to add/remove the GUI when needed, makes troubleshooting far easier on your server core. We will discuss this in more detail in a later post.

That’s it for now, keep an eye out for more Upgrade Issues and troubleshooting information. If you haven’t done this already, get your copy of the Windows Server 2012 today. If you do not have a TechNet/MSDN subscription or volume licensing agreement, feel free to try the fully functional, time limited evaluation versions here.

Vimal Shekar
Beta Support Engineer
Windows Core Team @ Microsoft