Outlook version is too old
Outlook installation is corrupted
User doesn't have access to outlook integration files
1. Check that you're running Office 2010 or newer.
2.Check that you're not running SAP with the Run as administrator option and Outlook as a regular user (Or vice versa). This the Outlook SDK can't handle (Not supported by Microsoft).
3. That you are using a 64-bit Outlook client and a 32-bit SAP client (Or vice verse). We cannot automate a 64-bit process if the add-on is 32-bit. You will need to use a 64-bit SAP client and a 64-bit B1UP.
4. Check that the users have Read & Execute Rights to the interop files that are located in: C:\Windows\assembly\GAC_MSIL\Microsoft.Office.Interop.Outlook\
5. Try to repair .net framework installation
6. Try to repair the office installation
Still not working?
In many cases, these errors can also be due to a corrupt Office installation. If above did not work we recommend you try and re-install the Office installation under Program and Features.