I was looking at client health percentage other day and found many systems were reported as not healthy though I fixed some of the machines with sccm client installed and able to receive policies.
Looked at Database for healthy computers and see double entries with different ResourceID ,client0 and HardwareID0 is NULL.
So what next ? I created collection with filter computers with sccm client installed and should be in computers with no sccm client.
SMS_R_SYSTEM.Client from SMS_R_System where
SMS_R_System.Name in (select name from SMS_R_System where SMS_R_System.Client is not null) and
SMS_R_System.Client is null
select name0 from v_R_System where client0 is null
and Name0 in( select Name0 from v_R_System where client0 =1)
order by name0
I see 100+ computers which are duplicate with same hostname but different value for ResourceID,client0 and hardwareID0 etc.
Special delete will remove them completely from database.