Re: Mass upgrade virtual hardware in 5.5?

Have you tried using something other than the web client?  PowerCLI would be excellent for this.  Here's a link to a guide:

http://psvmware.wordpress.com/2012/09/05/upgrade-virtual-machine-hardware-using-powercli/

Here's a script that's a lot more complicated but it does a lot more, too.

http://www.getshifting.com/wiki/powerclivmupgrade