After a recent install of vCenter 6.0 on a Window Server 2012 Machine I could not get the client integration plugin to work in the web client using Internet Explorer. After trying many things I finally resolved the issue by the following.

  1. Open internet options
  2. Click the Security Tab
  3. Add vCenter FQDN URL to the Local Intranet Zone
  4. Refresh Internet Explorer or close and reopen.

I also disabled the Windows firewall to make sure it was not blocking the port 8093