In the Data Collector List page in CA PC admin, the Data Collector has the status Unknown due to wrong DCM_ID environmental variable.
This is probably caused by an attempt to remove a former collector or reinstalling the collector.
The new DCM_ID will not match with the one in the DA and the Collector will have a status Unknown due to wrong DCM_ID environment variable.
All supported releases of Performance Management
Component: Data Collector
The configuration for the data collector is kept on the data aggregator (DA) so when the newly installed DC contacts the da with the old DCMID the da will send the configuration.