How to clear the Hardware Status warnings/errors in vCenter Server

To clear the warnings/errors from the Hardware Status tab:.  

• Go to Hardware Status tab and select the System event log view.
• Click Reset event log.
• Click Update. The error should now be cleared.
• Select the Alerts and warnings view.
• Click Reset sensors.
• Click Update. The memory should now be cleared.

If the error is not cleared, connect to the host via SSH.
Restart the sfcdb service.
To restart the service in ESXi, run this command:
services.sh restart
To restart the service in ESX, run this command:
service sfcbd restart
Click Update. The error should now be cleared.
For more information read the following article from VMware.