title: C# App Install Error - microsoft.visualstudio.hostingprocess.utilites.sync version 9.0.0.0 missing from Global Assembly Cache (GAC)
body: <p>Background: I have a winforms app written in C# that converts xlsx files to csv by calling a 2nd entirely seperate application ConvertExcelTo.Exe from the command line.  I'm using the Build Publishing tool to compile a setup / install file out of the solution for the winforms app.</p>
  
  <p>Problem: The Windows installer completes without any errors on my computer with Windows 7 Ultimate, Visual Studio 2010 Premium, and Framework 3.5 but the user operating on Windows XP SP3 without VS gets the following installation error message:</p>
  
  <pre><code>   This application requires microsoft.visualstudio.hostingprocess.utilites.sync 
     version 9.0.0.0 be installed in the Global Assembly Cache (GAC) first.
  </code></pre>
  
  <p>Under Prerequisites I have selected:</p>
  
  <ul>
  <li>Windows Installer 3.1</li>
  <li>.Net Framework 3.5</li>
  <li>Download prerequisites from the component vendor's website</li>
  </ul>
  
  <p>Under Application Files I have:</p>
  
  <ul>
  <li>Included Files: CCP_Utility.exe, CCP_Utility.exe.config, CCP_Utility.exe.manifest, ConvertExcelTo.exe, ExcelConversion.dll, Icon1.ico, Microsoft.Office.Interop.Excel.dll, Microsoft.Vbe.Interop.dll, office.dll</li>
  <li>Excluded Files: CCP_Utility.vshost.exe, CCP_Utility.pdb</li>
  <li>Prerequisite Files: Microsoft.VisualStudio.HostingProcess.Utilities.Sync.dll, stdole.dll</li>
  </ul>
  
  <p>I've tried:</p>
  
  <ul>
  <li>Adding the existing items ConvertExcelTo.exe and ExcelConversion.dll to the Project Solution and deleting the References to these files externally</li>
  <li>Excluding ConvertExcelTo.vshost.exe from the Application's Files under the Build Pubisher and deleting the file from the Solution</li>
  <li>Installing the Windows 4.5 SDK for XP SP3 &amp; Vista here: <a href="http://download.microsoft.com/download/7/c/4/7c426dfc-46e2-4ded-bab4-3b33600ad7d1/msi45sdk.msi" rel="nofollow">http://download.microsoft.com/download/7/c/4/7c426dfc-46e2-4ded-bab4-3b33600ad7d1/msi45sdk.msi</a> </li>
  </ul>
  
  <p>Question:</p>
  
  <ul>
  <li>What does the user have to download to get the installer to complete without errors?</li>
  <li>What do I need to edit in the Publisher so that other users don't get this error?</li>
  <li>Should I set any of the prerequisite files to be included files?  </li>
  </ul>
  
  <p>Thanks for looking! :) </p>