When reinstalling the ConfigMgr agent, the installation succeeds but the initialization does not. The machine is getting the same SMS GUID it had before although the SMSCFG.ini in c:\Windows was deleted and doesn’t show up in the ConfigMgr console. In MP_Registration.log you find these entries:
[RegTask] – Client is not registered. Sending registration request for [old GUID]
[RegTask] – Client registration is pending. Server assigned Client ID is GUID:[new GUID]
[RegTask] – Sleeping for 60 seconds.
[RegTask] – Client registration is pending. Sending confirmation request for GUID:[new GUID]
[RegTask] – Sleeping for 60 seconds.
[RegTask] – Client registration is pending. Sending confirmation request for GUID:[new GUID]
To resolve the issue, uninstall the client.
Delete the SMSCFG.ini in c:\windows and delete the machine certificates that you find in SMS\Certificates.
Reinstall the client and watch the MP_Registration.log
Mind that the registration may also be prevented if the ISRevoked flag is set for a particular GUID in ClientKeyData table. To check, run
Select * from ClientKeyData where SMSID like ‘[GUID]’
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