I recently had an issue with vmware’s vCenter where all virtual machines and hosts were showing as “Disconnected”. Nothing could be done in the control panel, but it functioned otherwise. Doing a quick search online, I didn’t see many results, so I restarted the instance, hoping the issue would self-resolve. However, the instance didn’t come back up after a restart. I explain how I resolved the problem, and give general troubleshooting tips to find problems.