title: VS2015 Update model from database - unexpected exception
body: <p>I have a solution with a lot of project.
  Few of them are using EDMX.
  It looks like I did something that crashed my EDMX files.
  When I open EDMX and click option "Update Model from Database" I get a exception popup windows with message:
  "An unexpected exception has occurred. The exception message is: 'Exception has been thrown by the target of invocation.'."</p>
  
  <p><a href="https://i.stack.imgur.com/LzHKB.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/LzHKB.png" alt="http://1drv.ms/20C9Vv0"></a></p>
  
  <p>And interesting is it doesn't matter which project. Any EDMX in the solution give me this bug. I have VS 2015 with latest EF 6.1.3.</p>
  
  <p>Please help me :)</p>