title: Object reference not set to an instance of an object in Page declaration
body: <p>I am having an issue with an existing site that was functioning until last week. When I open the site in VS 2013 I get a "Object reference not set to an instance of an object" error/warning on the page declaration of the <code>.aspx</code> pages and <code>.master</code> pages. The website builds correctly but when run only displays a blank page and no errors.</p>
  
  <p>I have verified that the code behind file exists and it's namespace and class are properly entered into the page declaration. Adding a new page to the project gets the same error and I have verified the references are all present. The website is with 3.5 framework. Any help would be appreciated. Thanks.</p>
  
  <p>Clayton</p>
  
  <p><img src="https://i.stack.imgur.com/Qsz3B.png" alt="Image of error message"></p>