Task Sequences Do Not Show Up for Unknown Computers

Problem

While using PXE or USB Boot Media for SCCM, some or all Task Sequences may not show up while trying to build a new Unknown Computer.

In our case we have a CAS and two Primary Sites and found that the Task Sequences did show when imaging within the boundaries of one of the Primary Sites but not the other.

Resolution

This can happen if a ConfigMgr Client object shares the same SMS Unique Identifier as the built-in x64 Unknown Computer object.

  1. Identify client(s) sharing the same SMS Unique Identifier as the built-in object(s) by running the following SQL Query:
/* Get Machines Sharing Unknown Computer GUID */
SELECT sys.Name0, sys.SMS_Unique_Identifier0, un.Description0 AS 'Built-In Unknown Computer Object', un.SiteCode0
FROM v_R_System AS sys LEFT OUTER JOIN
UnknownSystem_DISC AS un ON sys.SMS_Unique_Identifier0 = un.SMS_Unique_Identifier0
WHERE sys.SMS_Unique_Identifier0 IN (SELECT SMS_Unique_Identifier0
FROM UnknownSystem_DISC)
  1. Generate a new GUID for the client by performing the following actions on the client machine (PowerShell).
Stop-Service -Name ccmexec
del C:\Windows\SMSCFG.ini
Remove-Item -Path HKLM:\Software\Microsoft\SystemCertificates\SMS\Certificates\* -Force
certutil –delstore SMS SMS
Start-Service -Name ccmexec 
  1. After performing the above steps, force a Discovery Data Collection cycle from the client machine.

Note:  It may also be necessary to delete the existing ConfigMgr Client object from the SCCM console prior to performing these steps. We did in our instance but I think generating the new GUID and forcing Discovery was likely all that was needed.

Allow some time for replication (15mins) and then attempt imaging with the Unknown Computer again.

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