title: VSTO Excel Customization not loading in workbooks : Element not found. (Exception from HRESULT: 0x80070490)
body: <p>I am working with VSTO Excel project and customizing the xltx template. First release of the project is working correctly and users created workbooks from that template. I have added new worksheet and some controls in the template and released new version of project. This is working correctly only if user creates new workbook from template but all previously created workbook are throwing exception </p>
  
  <blockquote>
    <p>"Element not found (Exception from HRESULT: 0x80070490)". Any
    suggestion?</p>
    
    <p>************** Exception Text ************** System.Runtime.InteropServices.COMException (0x80070490): Element not
    found. (Exception from HRESULT: 0x80070490)    at
    Microsoft.VisualStudio.Tools.Office.Runtime.Interop.IHostItemProvider.GetHostExtender(String
    extenderType, String extenderCookie, IntPtr&amp; extenderObject)    at
    Microsoft.VisualStudio.Tools.Office.Runtime.DomainCreator.ExecuteCustomization.Microsoft.Office.Tools.IHostItemProvider.GetHostExtender(Type
    primaryType, String primaryCookie)    at
    Microsoft.Office.Tools.Excel.ControlSiteImpl..ctor(IServiceProvider
    serviceProvider, IHostItemProvider hostItemProvider, String
    primaryCookie, String identifier, Object containerComponent, UInt32
    officeVersion, Control control, _OLEObject extenderControl, Boolean
    isDynamic)    at
    Microsoft.Office.Tools.Excel.FactoryImpl.Microsoft.Office.Tools.Excel.Factory.CreateControlSite(IServiceProvider
    serviceProvider, IHostItemProvider hostItemProvider, String
    primaryCookie, String identifier, Object containerComponent, Control
    control)    at
    Microsoft.Office.Tools.Excel.Controls.Button..ctor(Factory factory,
    IHostItemProvider hostItemProvider, IServiceProvider serviceProvider,
    String cookie, String extenderCookie, Object container, String
    identifier)    at CampaignMapping.Excel.Beta.Tag.InitializeControls() 
    at CampaignMapping.Excel.Beta.Tag.Initialize()<br>
    Microsoft.VisualStudio.Tools.Office.Runtime.DomainCreator.ExecuteCustomization.ExecutePhase(ExecutionPhases
    executionPhases)    at
    Microsoft.VisualStudio.Tools.Office.Runtime.DomainCreator.ExecuteCustomization.Microsoft.VisualStudio.Tools.Office.Runtime.Interop.IExecuteCustomization2.LoadEntryPoints(IntPtr
    serviceProvider)</p>
    
    <p>************** Loaded Assemblies ************** </p>
  </blockquote>
  
  <p>(remainder removed for clarity of question as unnecessary for trouble-shooting of the reason)</p>