VMware vSphere error – Reset System Health for One or More Sensors

Issue

VMware ESXi vSphere client host Health Status (Configuration tab) shows Unknown and Question marks (?) next to each component.

Trying to Reset Sensors fails with error:

Error
A general system error occurred: Reset System Health Failed for One or More Sensors
Call “HostHealthStatusSystem.ResetSystemHealthInfo” for object “healthStatusSystem” on ESXi <server> failed.”

Resolution

Issue was resolved by restarting CIM Server.

• Go to Configuration tab > Security Profile (in Software section)
• Click on Properties (next to Firewall section) 
• Select CIM Server and click Options
• and then Restart

DELL PowerEdge 2950
VMware ESXi 5.0