title: Visual Studio 2017 builds all project because of "missing" PDB file
body: <p>I had a few minutes this morning to try to figure out why Visual Studio 2017 rebuild <em>all</em> of my projects in the solution every time I try to run the project.  I think I know <em>why</em> this is happening but I'm not sure how to fix it.</p>
  
  <p>I saw these articles:</p>
  
  <p><a href="http://michaelscodingspot.com/2017/04/28/visual-studio-keeps-rebuilding-projects-no-good-reason/" rel="nofollow noreferrer">http://michaelscodingspot.com/2017/04/28/visual-studio-keeps-rebuilding-projects-no-good-reason/</a></p>
  
  <p><a href="https://ofekshilon.com/2015/08/16/visual-studio-projects-that-just-keep-rebuilding-or-how-quantum-mechanics-mess-up-your-build/" rel="nofollow noreferrer">https://ofekshilon.com/2015/08/16/visual-studio-projects-that-just-keep-rebuilding-or-how-quantum-mechanics-mess-up-your-build/</a></p>
  
  <p>Which got me to turn up build logging.</p>
  
  <p>I now see that VS is looking for PDB files in the OBJ directory and since they are not there(1), VS thinks the project needs to be rebuilt.</p>
  
  <pre><code>3&gt;Project '****.Common' is not up to date. Missing output file 'C:\*******\***\****.Common\obj\Debug\***.****.Common.pdb'.2&gt;Build started.
  </code></pre>
  
  <p>1) The PDB files are <em>not</em> in the OBJ directory for the <em>assembly</em> projects.  They are in the BIN directory.  Note that in the main "executable" <em>web</em> project the PDB files are in both the OBJ and BIN directories.</p>
  
  <p>So now I need to make visual studio do one of the following:</p>
  
  <ul>
  <li>Put a copy of the PDB in the OBJ directory for <em>all</em> projects</li>
  <li>Make VS check in the BIN directory for the PDB</li>
  </ul>
  
  <p>I did some search but haven't been able to figure out a good set of search terms to find the answer to this one.</p>
  
  <p><em>Note this is a project that has been developed using VS2012, VS2015, VS2017 and maybe some before 2012, so this might be part of the problem.</em></p>