November, 2013

  • Windows Azure IaaS Host OS Update Demystified

    Special thanks to Sri Harsha for reviewing this post!! In this post we will look at: Why Windows Azure updates the host OS? How does the host OS update take place? What are availability sets? How does creating availability sets make more
  • Understanding ARM Assembly Part 1

    My name is Marion Cole, and I am a Sr. EE in Microsoft Platforms Serviceability group.  You may be wondering why Microsoft support would need to know ARM assembly.  Doesn’t Windows only run on x86 and x64 machines?  No.  Windows has more
  • Windows Azure Learning Resources

    Microsoft has loads of resources to help you learn, understand and leverage Windows Azure cloud platform. This is our effort of listing the resources that are available to help you learn about the Windows Azure architecture, security, features and implementation more
  • The [The selected task “{0}” no longer exists…] issue

    Good morning AskPerf! Over the past couple of years, our customers have opened Support Cases and created forum posts  on the following error when opening Task Scheduler on Windows 7 clients and Windows 2008 R2 Servers:

    The selected task “{0}” no longer exists. To see the current tasks, click Refresh.


    After you click OK to the additional messages, Scheduled Tasks will disappear:


    Note your tasks are actually there, but because of this issue, they cannot be seen in the GUI.

    There have been multiple resolutions to resolve this issue, however the fix below may be the easiest:

      1. Re-create the missing Scm folder under “%windir%\System32\LogFiles


    1. Restart your machine

    You should now be able to open Task Scheduler and see your tasks, or at the very least, find the particular task that is triggering this error.

    Unfortunately, we are unsure why the Scm folder is getting removed, but can speculate Malware, an Administrator cleaning up files/folders, etc.

    If this does not resolve your issue, check the blog post below which points to other resolutions by our forum members.

    Error message 'The selected task "{0}" no longer exists. To see the current tasks, click Refresh’

    Note this blog post will be updated as new information becomes available.


  • Staying updated with all things Windows Azure

    Windows Azure is an ever evolving Microsoft cloud platform. You may find it tough to stay updated with all the latest features, current news and technical know how’s. To help you stay updated with all thing Azure, we have put together a list of more
  • Unable to create a Storage Space in Windows 2012 R2 when using Windows Azure data disks

    We recently determined Windows 2012 R2 Storage Spaces is incompatible with the virtual hard drives (VHDs) created by Windows Azure for use as data disks. Not only will the disks not enumerate in Server Manager, but they will also show up as CanPool=false when enumerated using Get-PhysicalDisk in PowerShell. The same VHDs work fine when used with Windows 2012.The root cause of the problem is that the physical disk size advertised by Azure VHDs isn’t compatible with Windows 2012 R2 Storage Spaces.

    A fix is under development and is currently targeted for deployment in January 2014. In the meantime, if you need to leverage Storage Spaces to improve IOPS performance, you should continue to use Windows 2012 for your workload. Then, once the fix has been released, you can either migrate your workload to Windows 2012 R2 or upgrade your Windows 2012 virtual machines to Windows 2012 R2.

  • Windows Server 2012/2012R2 – When Physical disks are attached to a virtual machine, Hyper-V Replica will have to be disabled

    Hello Everyone,

    Many of you have come across issues with respect to Hyper-V replication in Windows Server 2012 and 2012R2.

    In this blog, we are going to address an occurrence that you might run into when enabling Hyper-V Replica. In Replica, you cannot enable a Virtual Machine with a physical disk attached to it (iSCSI, physical disk, and Synthetic Fibre Channel) This is by design. Below is a screenshot of the error message you will receive.




    Hyper-V Replica works by tracking all writes that go to the virtual hard disks attached to the VM. The write commands are then saved to a log file and shipped to the Replica server. From there, it is applied on the replica virtual machine.

    The logic used for tracking these writes is implemented in a driver called VHDMP.SYS that runs on the host machine.

    This driver only tracks writes that go to VHD files; it does not track the writes that go to any physical disk that are attached to the virtual machine.

    Similarly – any physical disks that are connected within a VM are invisible to the host machine and hence VHDMP.SYS does not see these disks.

    As a result, the physical disks that are connected cannot be replicated to the destination.

    Work Around:

    Replication can be done before any physical disks are connected to the Virtual Machine. After replication is completed, add the physical disks back.

    In the case of iSCSI attached physical disk:

    • Remove the targets and stop the iSCSI service.
    • Replicate the Virtual Machines and then after replication is done, start the service and then add the targets. This has to be done anytime you wish to replicate the VM over as we will again detect any physical disk upon the next replica cycle (5 minutes in Server 2012 and configurable in Server 2012 R2).

    Hope this is of help to all of you.

    For more information about Hyper-V Replica, see:

    Deploy Hyper-V Replica

    Configuring Hyper-V Replica in Windows Server 2012

    More to come soon.

    Suganya Natarajan
    Support Engineer
    Windows Core Team

  • Activating virtual machines via Automatic Virtual Machine Activation in Windows Server 2012 R2


    My name is Mayank Sharma and I am a Support Engineer in Windows Platforms Support Team. In this blog, I am going to discuss a very exciting addition to Windows Server 2012 R2, called as AVMA (Automatic Virtual Machine Activation). As the name suggests, this feature allows automatic activation of virtual machines running on Windows Server 2012 R2 Hyper-V hosts.

    What makes AVMA attractive?

    1. AVMA is perfect for hosted environments where virtual machines do not have access to the internet or the hoster’s network.
    2. The Hyper-V host will work as a sort of ‘activation server’ for virtual machines, activating the machine without the need of a network or any kind of intervention from the administrators.
    3. There is no additional hardware or software requirement.

    Before I start, let me first remind you that this feature available only if the following conditions are true:

    • The Hyper-V host is a Windows Server 2012 R2 Datacenter Edition.
    • The VMs are running Windows Server 2012 R2, thus only the below three editions can get activated by AVMA
      • Windows Server 2012 R2 Standard
      • Windows Server 2012 R2 Datacenter
      • Windows Server 2012 R2 Essentials
    • The Hyper-V host is activated. (It can be activated using any of your regular activation mechanisms like MAK, OEM or KMS.)
    • The Guest VMs have AVMA client key installed on it. (more about this later)

    This means that Windows Server 2012 VMs are not eligible for AVMA activation even if they are hosted on a 2012 R2 Hyper-V host. Similarly Windows Server 2012 Hyper-V hosts cannot activate VMs running Windows Server 2012 or 2012 R2 guests through AVMA.

    Setting up for AVMA:

    This is a one step process. Once the Hyper-V host is activated and guest virtual machines are running smoothly (without activation off course!), the only step is to install the AVMA client key on the guest Hyper-V machine. This link lists the AVMA client keys for the SKUs that supports AVMA: If you control the installation of the operating system – it is easier to supply the AVMA key during installation either manually or by using an answer file. To manually install the key using Command line use the following Syntax from an administrative Command prompt:

    slmgr.vbs /ipk <AVMA_Client_Key>

    Once this is done you just have to sit back and relax!

    The ‘activation’ process:

    When a guest VM starts (or needs to activate again e.g. activation getting close to timing out) the guest uses the AVMA pipeline build inside the virtualization layer of hyper v to pass an encrypted packet to the host mentioning the following information along with the activation request: Which SKU it is running, The license state, The unique VM ID and data that will be logged inside the hyper v host’s event log corresponding to this activation request.

    Host responds via the same AVMA pipe to the guest, an encrypted packet comprised of Activation approval/rejection, Host hardware ID and a signed version of the request packet that was sent by the guest (which can be used for verification purposes).

    Note again that this whole process does not require a network connection of any sort between the host and guest, so if a VM is in a private network, it can still leverage AVMA activation. The Data Exchange Integration Service is used instead for this purpose. So let’s make sure that it is checked under the Integration Services in the virtual machine’s settings as shown below.


    After an activation request is sent, the following is registered in the application logs of the guest virtual machine


    Look for the Event ID 12309. It is not as verbose as the conventional KMS events.

    The Hyper-V host also registers the logs about processing the activation requests coming from the client virtual machine as shown below.


    Once the guest VM gets activated and you run slmgr.vbs /dlv on the guest, you should see something like this:


    While KMS activation is valid for 180 days, AVMA activation is valid only for 7 days. If you see closely under description, it displays “VIRTUAL_MACHINE_ACTIVATION”, suggesting that the virtual machine is indeed activated by AVMA (just in case you little too skeptical), also look at expiration interval saying that the activation is valid for 7 days. What this means is that after 7 days the guest machine will contact the host again using the same procedure to get itself activated again, no user intervention is required.

    This is the happy ending of the story. An activated world is much more colorful and joyous!

    Thank you for reading, until next time, keep your windows activated...

    Mayank Sharma
    Support Engineer
    Windows Platforms Support Team

  • The Compiler Did What?

    I was recently investigating a crash in an application.  As I researched the issue I found a very old defect in the code that was only recently being exposed by the compiler.   The crash occurred at the below instruction because the ebx register more
  • Heads up: Perfmon algorithm issue found/fixed

    One of our Escalation Engineers has posted the following blog on the NTDEBUGGING page:

    Performance Monitor Averages, the Right Way and the Wrong Way

    Recently we have found that under some conditions perfmon will use the incorrect algorithm to calculate averages.  When reading from log files perfmon has been formatting the values, summing them, and dividing by the number of entries.  This issue has been corrected in perfmon for Windows 8/Server 2012 with KB2877211 and for Windows 8.1/Server 2012 R2 as part of KB2883200.  We recommend using these fixes when analyzing perfmon logs to determine the average of a performance counter.  Note that KB2877211/KB2883200 only change the behavior when analyzing logs, there is no change when the data is collected.  This means you can collect performance logs from any version of Windows and analyze them on a system with these fixes installed.

    Windows 8 / Server 2012 hotfix link

    Windows 8.1 / Server 2012 R2 hotfix link