Just to check if it's a simple fix....do you still have ACADE 2012 & Vault Client 2012 installed? When we upgraded, we kept 2012 installed for awhile. This means that the Vault add-in for ACADE 2012 was still installed, and you can't install the Vault add-in for ACADE 2013 until the old add-in is removed. We noticed that it took forever to login with the Vault add-in while using ACADE 2013.
So the solution was to uninstall Vault Client 2012, and go into Add/Remove features of Vault Client 2013 and check the Vault add-in for AutoCAD Electrical 2013. Now his add-in is loading like normal again. Hope this helps