Imaging so-called unknown computers (computers that are not in the SCCM database) in SCCM 2012 requires a bit of prep work and an understanding of the deployment process. This guide dives into unknown objects, distribution point changes, and task sequences.

Operating System Deployment (OSD) under Microsoft Deployment Toolkit (MDT) control is radically different from OSD with SCCM. This is even true with SCCM/MDT integration. We can really think of MDT as a pulling deployment solution. From bare metal to a refresh, actions tend to be client-driven (though not always). SCCM, for the most part, is a push deployment solution.

For example, an administrator would not make task sequences available to every device. Bad things can happen. This can make it difficult for an SCCM administrator to manage new and unknown computers. Let’s look into the process and changes needed to image unknown computers in SCCM 2012.

Understanding unknown computers in SCCM 2012

For me, the largest barrier to overcome was unknown computer deployments. These are OS deployments to machines not found in the SCCM database or those that your SCCM infrastructure is not currently managing. Unknown machines can also include devices that an admin has not manually imported into SCCM. If SCCM doesn’t recognize the MAC or BIOS GUID, it is an unknown computer.

By default, the Device Collections root contains an All Unknown Computers collection. This collection contains two objects: x64 Unknown Computer and x86 Unknown Computer.

Members of the All Unknown Computers collection in SCCM 2012

Members of the All Unknown Computers collection in SCCM 2012

These objects represent the architecture of the unknown computer, not the current OS on the machine. The x86 unknown computer applies to machines that can only support an x86 OS, whereas the x64 unknown computer applies to machines that can support x86 and x64 operating systems.

Deploying your task sequence and configuring collection variables

This guide won’t cover the creation of a SCCM task sequence; the creation process is identical for known and unknown computers. However, unknown computer imaging does require a bit of tweaking to make the process run smoothly.

Your task sequence must include a method of installing the Configuration Manager client. The Setup Windows and the ConfigMgr task normally handle the installation, so an unaltered task sequence would work fine. If the Configuration Manager client installation fails (or if the task sequences fail early enough), the imaging device will be registered with the name “Unknown.” Objects linked to an unknown record do not fall under the All Unknown Computers collection. You should delete an unknown device record before you reimage the machine.

An Unknown device record in an SCCM database

An Unknown device record in an SCCM database

Decide whether your task sequence will be an assignment (available) or a mandatory (required) deployment. A required deployment is interaction-less. It will not prompt for any information. An assignment will allow you to direct the OS installation path. You can select a task sequence if multiple devices are deployed, and you can assign a computer name before the installation occurs.

An available deployment to the All Unknown Computers device collection

An available deployment to the All Unknown Computers device collection

There are multiple ways to prompt for a computer name. My favorite, which works with an MDT integrated task sequence, is to assign a collection variable to the All Unknown Computers collection.

In the Configuration Manager console, navigate to Assets and Compliance/Device Collections. Open the Properties tab on the All Unknown Computers collection and select Collection Variables. Add a collection variable and set the name to OSDComputerName. Leave the value blank.

Creating the OSDComputerName variable for Unknown Computers

Creating the OSDComputerName variable for Unknown Computers

When an unknown computer begins a task sequence, you will be able to configure the computer name by clicking the OSDComputerName variable and entering a machine name.

Distribution point requirements for unknown computer support

Your distribution point must also support unknown computers in order for them to network boot. Navigate to Administration/Site Configuration/Servers and Site System Roles in the Configuration Manager console. Under Site System Roles, select the Distribution point properties for any DP that will need unknown computer support.

Enabling unknown computer support on the distribution point

Enabling unknown computer support on the distribution point

Ensure that the following options are selected:

  • Enable PXE support for clients
  • Allow this distribution point to respond to incoming PXE requests
  • Enable unknown computer support

Example of a distribution point that can now support unknown computer deployments

Example of a distribution point that can now support unknown computer deployments

If you use device media, ensure that the Enable unknown computer support box was selected when the media was created.

Unknown computer support in SCCM can require a different way of thinking and does require some infrastructure changes. By using the All Unknown Computers collection, you can deploy task sequences to machines that SCCM does not manage. Assigning a task sequence and configuring a collection variable allows you to have some control at the machine level. Finally, enabling unknown computer support on the distribution point allows you to image devices that SCCM does not know.

In my next post I will show you how to troubleshoot unknown computer deployments.

  1. Avatar
    Mark 8 years ago

    Dear Joseph, I liked your description about Imaging unknown computers through SCCM. As i am a newbie to SCCM, I have one question… What if some guest comes to organization with personal laptop and connect it to Organization’s network(with is in the Distribution group boundary). Will it consider it as unknown computer and start Imaging it?

  2. Avatar Author

    It will only image if they physically hard wire the laptop and then PXE boot it. That is highly unlikely.

  3. Avatar
    LoganIN 7 years ago

    Hi Joseph,


    As per your instruction I have enabled osdcomputername on all unknown computers and now it’s prompting to enter the computer name. But I am facing few issues while imaging

    1. Unable to deploy os for agent installed machines even after deleted the machine name from sccm console.

    2. I have entered the computer name using collection variable’s but after booting the computer name has been changed to something else. We are using captured image to deploy the os. Will it work on captured image ?


  4. Avatar
    chandra 7 years ago

    Hi Joseph,

    I have a large network of server but SCCM we are able to see only x Number but in total we have x+ servers deployed please guide me how to find the remaining missing servers and install SCCM client into it. all are window machines only.


  5. Avatar
    Winston Jordan 5 years ago

    Thank you for this! I recently installed SCCM in our environment and that deployment to Unknown devices was what I was missing!

  6. Avatar
    Mark Rogalski 5 years ago

    Bam! This wasexactly the missing info I needed to get my fresh out of the box PCs imaged, thanks!

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