SCCM Cannot Build Unknown Machines

Update: Microsoft suggest (despite the ambiguous wording) that the latest hotfix does resolve this issue. It may also be worth updating your boot images after applying the hotfix to ensure the fix applies.

This is a bug introduced in SCCM version 1702 where unknown machines can not be built as they cannot find a task sequence. The main symptom is unknown machines will reboot before you get to the SCCM password screen when network booting – you will see the background image.


  1. Run this query on the database to find computers matching the GUID: select * from System_DISC where SMS_Unique_Identifier0 like ‘%ce458683-a99a-4898-97dd-85e72e1478ab%’
  2. Remote onto the machine identified in step 1
  3. Stop the service SMS Agent Host on the machine
  4. Delete the machine from the SCCM console
  5. Delete C:\Windows\smscfg.ini on the machine
  6. Start the service SMS Agent Host on the machine


Step 1 assumes the Unknown Computer GUID. If that finds no results it may be the case that there are new Unknown Computer objects (this may happen when upgrading SCCM for example).

To find the Unknown Computer GUIDS, run the following query on the database: select * from System_DISC where SMS_Unique_Identifier0 like ‘%ce458683-a99a-4898-97dd-85e72e1478ab%’


How to run a query

  1. RDP to uiwdbsms03
  2. Launch SQL Server Management Studio
  3. Connect to UIWDBSMS03
  4. Expand Databases
  5. Right click on UN2 and select New Query
  6. Paste in the query and click Execute
  7. The results in this example show the offending computer that has stolen the GUID


Leave a Reply

Your email address will not be published. Required fields are marked *