title: Excel 0x800A03EC Error
body: <p>I was getting [UNKNOWN] Exception from HRESULT: 0x800A03EC--ERROR at this line in my Windows Server 2008 which is running Office 2003: </p>
  
  <pre><code>excelApp.Workbooks.Open(path, 0, false, 5, "", "", false, 
      Excel.XlPlatform.xlWindows, "",true, false, 0, true);
  </code></pre>
  
  <p>I had multiple applications running which generate excel reports. Most of them use </p>
  
  <pre><code>Excel._Application excelApp = new Excel.Application();
  </code></pre>
  
  <p>All of these applications failed except one application which had </p>
  
  <pre><code>ApplicationClass excelApp=new ApplicationClass();
  </code></pre>
  
  <p>So, I updated the first failed application to use <code>ApplicationClass</code> instead of <code>Excel.Application</code>. That solved the issue and I did not get <code>0x800A03EC</code> error anymore on the app. </p>
  
  <p>But to my surprise all the rest of the failed applications are not getting this error anymore. There hasn't been any other change made to the server. I even reverted the change I made on the first application and even it is running fine without the error.</p>
  
  <p>Has anyone experienced this issue? I see that this server does not have Microsoft Excel under DCOM Config in the component services. Is this somehow related? </p>