could you try out:
seems IE11 is not compatible with NPAPI Plugins: http://answers.microsoft.com/en-us/ie/forum/ie10-windows_7/are-npapi-plugins-still-compatible-with-internet/33f86c67-6387-4d60-ac5a-150f45c762dd?auth=1
But maybe the NPAPI activate on Chrome works for you also .
Indeed - thank you the plug ins worked in Chrome. I'm just wondering why the plugin in worked in IE11 with Vsphere 5.5 and stopped working with Vsphere 6
There are some solutions to your problem, take a look on this another post: vSphere Web Client integration plugin problems in Windows 8.1
Recently I got this problem after upgrade a customer vCenter to version 6 and the solution was add the vCenter URL to Local Intranet zone.---
Senior Infrastructure Specialist
I was also able to get it work in IE after tweaking some security settings. I did add the site to the local intranet zone.