title: Unable to cast COM object of type 'System.__ComObject' to interface type 'Microsoft.Office.Core.IRibbonUI'
body: <p>Hi I am new to excel addin. i had installed microsoft office 2010 and my addin used to work perfectly. To verify in 2013 i had installed 2013 and was running both version 2010 and 2013. Recently i installed 2013 and now if i open 2010 version my addin loads but gives following error. please help</p>
  
  <p>Error </p>
  
  <pre><code>An exception was thrown with the folowing information: System.Runtime.CallbackException: A user callback threw an exception.  Check the exception stack and inner exception to determine the callback that failed. ---&gt; System.InvalidCastException: Unable to cast COM object of type 'System.__ComObject' to interface type 'Microsoft.Office.Core.IRibbonUI'. This operation failed because the QueryInterface call on the COM component for the interface with IID '{000C03A7-0000-0000-C000-000000000046}' failed due to the following error: Library not registered. (Exception from HRESULT: 0x8002801D (TYPE_E_LIBNOTREGISTERED)).
  at System.StubHelpers.StubHelpers.GetCOMIPFromRCW(Object objSrc, IntPtr pCPCMD, IntPtr&amp; ppTarget, Boolean&amp; pfNeedsRelease)
  at Microsoft.Office.Core.IRibbonUI.InvalidateControl(String ControlID)
  at myaddin.Wrappers.Office.Ribbon.Impl.Ribbon.InvalidateControl(String controlId) in c:\iraddin\IR_Addin\myaddinOfficeLink\Main\src\myaddin.Wrappers.Office\Ribbon\Impl\Ribbon.cs:line 37
  at myaddin.Common.Ribbon.RibbonManager.InvalidateControl(String controlId) in c:\iraddin\IR_Addin\myaddinOfficeLink\Main\src\myaddin.Common\Ribbon\RibbonManager.cs:line 66
  at myaddin.Common.Ribbon.RibbonManager.OnControlChanged(Object sender, ControlChangedEventArgs e) in c:\iraddin\IR_Addin\myaddinOfficeLink\Main\src\myaddin.Common\Ribbon\RibbonManager.cs:line 360
  at myaddin.Wrappers.Office.Ribbon.ControlsProxy.RibbonControlsManager.OnControlChanged(Object sender, ControlChangedEventArgs e) in c:\iraddin\IR_Addin\myaddinOfficeLink\Main\src\myaddin.Wrappers.Office\Ribbon\ControlsProxy\RibbonControlsManager.cs:line 57
  at myaddin.Wrappers.Office.Ribbon.ControlsProxy.ControlProxyBase.RaiseControlChanged() in c:\iraddin\IR_Addin\myaddinOfficeLink\Main\src\myaddin.Wrappers.Office\Ribbon\ControlsProxy\ControlProxyBase.cs:line 110
  at myaddin.Wrappers.Office.Ribbon.ControlsProxy.ControlProxyBase.set_IsEnabled(Boolean value) in c:\iraddin\IR_Addin\myaddinOfficeLink\Main\src\myaddin.Wrappers.Office\Ribbon\ControlsProxy\ControlProxyBase.cs:line 69
  at myaddin.Wrappers.Office.Ribbon.ControlsProxy.ButtonControlProxy.set_IsEnabled(Boolean value) in c:\iraddin\IR_Addin\myaddinOfficeLink\Main\src\myaddin.Wrappers.Office\Ribbon\ControlsProxy\ButtonControlProxy.cs:line 34
  at myaddin.Modules.Views.SupportView.UpdateControls() in c:\iraddin\IR_Addin\myaddinOfficeLink\Main\src\myaddin.Modules\Views\SupportView.cs:line 115
  at myaddin.Modules.Views.SupportView.AuthenticationStateEventHandler(Object sender, AuthenticationStateChangedEventArgs e) in c:\iraddin\IR_Addin\myaddinOfficeLink\Main\src\myaddin.Modules\Views\SupportView.cs:line 183
  at System.EventHandler`1.Invoke(Object sender, TEventArgs e)
  at myaddin.Office.Service.Contract.ClientImpl.AuthenticationServiceClient.OnAuthenticationStateChanged(Object sender, AuthenticationStateChangedEventArgs e) in c:\iraddin\IR_Addin\myaddinOfficeLink\Main\src\myaddin.Office.Service.Contract\ClientImpl\AuthenticationServiceClient.cs:line 150
  at myaddin.Office.Service.Contract.ClientImpl.AuthenticationServiceClient.OnOpened(Object sender, EventArgs e) in c:\iraddin\IR_Addin\myaddinOfficeLink\Main\src\myaddin.Office.Service.Contract\ClientImpl\AuthenticationServiceClient.cs:line 122
  at System.ServiceModel.Channels.CommunicationObject.OnOpened()
  </code></pre>