When installing operating systems using workstation management software (Configuration Manager), we may encounter a strange situation when a station previously unmanaged by ConfigMgr fails to install in Unknown Computer mode ("Unknown Computer"), and in the log of the installation attempt (SMSTS.LOG) we find that the computer is recognized as "Known". This type of situation tends to occur when the installation is allowed (OSD process) only for unknown computers. Then it usually means an attempt to install on a computer that was already a Configuration Manager client. If the installation attempt was not due to a mistake, it is usually enough to delete the computer object. However, in a small number of cases, the problem is not the result of a computer among Configuration Manager's clients.
Closer analysis of such cases usually reveals duplication of one of two (theoretically completely unique) identifiers:
1. MAC Address of the network card
2. SMBOS GUID
While in the case of the MAC address of the network card we have a built-in report to detect duplicate addresses (Computers with duplicate MAC address in the Site - Discovery and Inventory Information category), the case of duplicate SMSBIOS GUID we are on our own.
The construction of such a report is not complicated, the key to success here is the right SQL query:
SELECT SYS.ResourceID, SYS.Name0 as ComputerName, SYS.SMBIOS_GUID0 as [SMBIOS GUID], CS.Manufacturer0 as Manufacturer, CS.Model0 as Model
FROM v_R_System as SYS INNER JOIN v_GS_COMPUTER_SYSTEM as CS on SYS. ResourceID = CS. ResourceID
WHERE SYS.SMBIOS_GUID0 in (SELECT SMBIOS_GUID0 FROM (
SELECT SMBIOS_GUID0, COUNT(SMBIOS_GUID0) as Count
FROM v_R_System
GROUP BY SMBIOS_GUID0
HAVING COUNT(SMBIOS_GUID0) > 1
) as A
)
ORDER BY SYS.SMBIOS_GUID0, SYS.Name0
Results:
Creating a report allows you to get a list of computers whose SMSBIOS GUIDs are duplicated.
Concluding remarks.
1 Usually the report is dominated by anything suspicious stations whose manufacturer and model are not among the well-known brands, but there are exceptions.
2. to nevertheless install a station "conflicting" at the SMSBIOS GUID level, you can delete the object of an existing station (with the same SMBIOS GUID value), but this will destroy the history (e.g., inventory) for that station. The station itself will not fall out of management, as it will reappear in the Configuration Manager database after the next configuration cycle.