title: Visual Studio 2017: Project is out of date with error (0x80004005)
body: <p>Visual Studio 2017 Professional on Windows 10, solution with 47 projects targeting .NET 4.5.2.</p>
  
  <p>VS always rebuilds many projects in my solution even if unchanged and up to date.  I this "very informative" message:</p>
  
  <pre><code>1&gt;Project 'A' is not up to date. Error (0x80004005). 
  1&gt;------ Build started: Project: A, Configuration: Debug Any CPU ------
  2&gt;Project 'B' is not up to date. Error (0x80004005). 
  2&gt;------ Build started: Project: B, Configuration: Debug Any CPU ------
  </code></pre>
  
  <p>I cannot see any .suo files in the solution.  Some projects in the solution are C# and others are VB.NET.  However, as I was typing this, I notice that it is the C# projects only that throw the 0x80004005 error and compel rebuild.</p>
  
  <p>Please help me solve this weird problem.</p>
  
  <p>Thanks.</p>