If you’ve migrated (or attempted to!) to the vSphere Web Client and used it heavily if not exclusively, you’ve no doubt had it stop working on you. I’ve had to restart the service occasionally when the web interface seems to just die.
Restarting it is an easy process, it’s just not instant. Simply run the remote services applet (Services.msc) on a Windows system that is authenticated against the Windows server running the vCenter Server (I don’t have a how-to for the appliance).
You can simply restart the service, vspherewebclientsvc. If there are pending tasks in vCenter they will continue. This is NOT the case with the VMware VirtualCenter Server service.
Now, that was the easy part. The unfortunate part is that the service takes a while to fully resume. If you simply restart the service, that goes fine. There are a number of interprocess communication components to the vSphere Web Client. You may see this type of web page until it is ready:
During this time, you can still access the vSphere Client as a Windows application. But low and behold the vSphere Web Client will return and you’ll be able to log in.