Upgrading to Windows Server 2012 - Part 4

Known issues during an upgrade


Hi everyone,

Today I want to bring up some known issues in Hyper-V, iSCSI targets, and moving between Full Server, Server Core, and Minimal Server interface. We already have KBs out there to assist you in case you run into any of these issues. I have added links to these articles here:

Windows Server 2008 and Windows Server 2008 R2 virtual machines blue screen/lock up after upgrade to Windows Server 2012:

In some cases, we have seen that existing Windows Server 2008/2008 R2 virtual machines that were upgraded to Windows Server 2012, fail to boot after the Upgrade. Typically they would show you a blue screen and then reboot automatically, or lock up/stop responding completely during boot. The Stop code shown may be different each time, and dumps may or may not be generated. This may also cause other virtual machines running on the same host to hang or crash.

One of the reasons that we noticed – is if the hypervisor running the virtual machine is not able to handle the synthetic timer events in a proper fashion. We have released a hotfix that resolves this issue. This hotfix is applicable to both Windows Server 2008 and 2008 R2, and is a pre-requisite before you create Windows 8 or Server 2012 Virtual machines on these hosts. The below fix replaced KB2526776 that was released for the pre-RTM builds of Windows 8 and Windows Server2012.

You cannot run a Windows 8-based or Windows Server 2012-based virtual machine in Windows Server 2008 or in Windows Server 2008 R2

After an Upgrade, the hypervisor does not start, and complains that the hardware does not meet requirements:

We have seen multiple instances of this happen, where after an in place upgrade of the hyper-V host, the hypervisor fails to launch. The error warns that the hardware is not compatible, even though it is. The issue was traced and was found to be firmware related. The BIOS showed that some of the virtualization requirements like VT, DEP are enabled, but these were actually not enabled, or their states were misreported to the operating system. Our partners have already issued updated BIOS to fix these, and we released the following KB article for more information.

A BIOS update may be required for some computers to install the Hyper-V Role and/or start Hyper-V virtual machines

iSCSI Target is now available in-box:

Also, if you are using Microsoft iSCSI Software Target 3.3 on your Windows Server 2008 R2, ensure that you migrate the settings for the target and un-install the target before performing the upgrade. The iSCSI target feature comes in box with Windows Server 2012. You do not need to install a software target separately. All you need to do is install the sub-feature to get a fully functional iSCSI target. We published this KB article to run you through the steps:

Migrating iSCSI Target 3.3 settings before upgrading Windows Server 2008 R2 to Windows Server 2012

Unable to convert WS2012 from Server Core configuration to Full Server configuration if upgraded from WS2008/2008R2 Server Core:

We talked in brief about the three configurations in which you can run a Windows Server 2012, namely Server with a GUI (aka Full Server), Server Core and Minimal Server Interface (aka: MinShell). Unlike in earlier versions of Windows Servers, you can now move from one configuration to another by adding or removing the shell and management components.

However, remember that when performing upgrades from a down-level operating system, you can only upgrade to the same configuration levels, i.e.:

  • Windows 2008/2008 R2 Full Server -> Win 2012 Server with a GUI (cannot go to Server Core)
  • Windows 2008/2008 R2 Server Core -> Win 2012 Server Core only (cannot go to Server with a GUI)

Below is a simple diagram that summarizes how to add/remove the shell and management components to switch between one another. Note that in some cases when adding the feature back to the server, you may get an error stating that the sources are missing. This occurs because you are missing the payload needed for that role, and Windows is not able to automatically download this from Windows Update. In such cases, you may need to use the “ –Source” parameter in the command and show where the sources are. Mike Stephen’s blog talks about this in more detail:

Windows Server 2012 Shell Game




On a clean installation of Windows Server 2012, you are very unlikely to run into issues moving from one configuration to another. However, on an upgraded installation, here are some of the issues that were reported to us. If you upgrade from a Full installation of Windows Server 2008/2008R2 to Windows Server 2012 in Server with a GUI mode, and then switch to Server Core mode, and then try to convert back to Server with a GUI configuration – it will fail. Similarly, if you upgrade a Server Core edition of Windows Server 2008/R2 and you try to move this upgraded Server 2012 to Server with a GUI configuration, it would fail.

The reason for these failures was traced back to some migrated event publishers. You can resolve this by deleting these publishers from the registry. The following can be run from an administrative command prompt to accomplish this:

reg delete HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\WINEVT\Publishers\{bc2eeeec-b77a-4a52-b6a4-dffb1b1370cb}
reg delete HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\WINEVT\Publishers\{57e0b31d-de8c-4181-bcd1-f70e880b49fc}
reg delete HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\WINEVT\Publishers\{8c9dd1ad-e6e5-4b07-b455-684a9d879900}

After running these commands, restart the upgrade. More details about this issue are published in this KB article:

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

In the next blog, we will be talking about known issues related to Remote Management tools. Thanks for reading, hope these get you past any hiccups. Keep commenting below if you notice any issues during your upgrade.

Vimal Shekar
Windows Core Team @ Microsoft