While working, I came across a problem where Virtual Center hung on a task and all other tasks, like “maintenance mode”, “power down”, “migrate”, etc. where queued behind it. Therefor Virtual Center wasn’t operational anymore. Also Virtual Center became very slow and we could only hope that all functionalities would stay online.

I can hear you think: “Well, why don’t you just right-click on the task and cancel it?”, but that option was not available.

So what to do to resolve this issue? There two basic steps to get every think back to normal:
1. On the ESX host where the non-responding VM’s reside, open the console and login. Now enter the command “service mgmt-vmware restart”.
2. Login the Virtual Center host (Windows server), go to the services.msc and restart de service “VMware VirtualCenter”.