When moving a hard drive to a new machine for a hardware refresh, we notice that the agent connection doesn't seem to resume when the new machine is running, even though the name has not changed. We did notice that sometimes it does resume when moving drives but not often. Does the agent hold onto some other parameter other than the system name if the main drive is moved to a newer tower. 

The computers show up in EC as Offline. The EC Agent service on the machine is running but all options are greyed out so no change can be made like stopping and starting the agent service. EC agent has to be manually uninstalled from the machine and reinstalled for it to appear back online in EC. Doesn't seem to work if we uninstall the agent through EC and push agent through EC during these scenarios.