Unable To Cast COM Object Of Type 'Microsoft.Office.Interop.Outlook.ApplicationClass' To Interface Type 'Microsoft.Office.Interop.Outlook._Application'. This Operation Failed Because The QueryInterface Call On The COM Component For The Interface With IID

Send Outlook Mail Message activity is not working and get the following error " Unable to cast COM object of type 'Microsoft.Office.Interop.Outlook.ApplicationClass' to interface type 'Microsoft.Office.Interop.Outlook._Application'. This operation failed because the QueryInterface call on the COM component for the interface with IID '{00063001-0000-0000-C000-000000000046}' failed due to the following error: Library not registered."

Root Cause: The issue is caused by a wrong registry file, this happens when the version of Microsoft Office is downgraded. Example from 2010 to 2007.

Investigation Steps:

  1. Open the regedit.exe and navigate to the below place.
  • Registry Key: HKEY_CLASSES_ROOT\TypeLib\{00062FFF-0000-0000-C000-000000000046}
  1. Here folders with numbers: 9.3, 9.4 or 9.5 will be present and it depends of the versions of the Microsoft Packages


Outlook 2007 9.3
Outlook 2010 9.4
Outlook 2013 9.5
Outlook 2016orO365 9.6

  1. So when downgraded, these folders are not deleted, if navigated from Office 2010, the 9.4 will be present together with 9.3 from Office 2007.

Resolution: Delete the folder related to the Microsoft Office that is not installed in the computer.


If 9.4 folder (from Office 2010) is present and Office 2007 (folder 9.3) is used, it is recommended to delete the folder 9.4, related to the Office 2010 that is not installed in computer, inside the registry key:

  • HKEY_CLASSES_ROOT\TypeLib\{00062FFF-0000-0000-C000-000000000046}