I'm getting an interface format error! (Registry error)

Have you encountered the following error while using Outlook?

Interface format error

System.InvalidCastException: 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 ID '{00000000-0000-0000-C000-000000000000}' failed due to the following error: Library not registered. (Exception from HRESULT: 0x8002801D (TYPE_E_LIBNOTREGISTERED)).

Cause

This error occurs due to an incorrect registry value when two Office versions are installed and used.

Resolution

Check the registry values for errors and delete the duplicate version.

If the issue persists even after deletion, please contact Microsoft Support.

1. Launch the Registry Editor (regedit) from the Start menu (search bar).

A. Type the following path in the Start screen of the Registry Editor. (Outlook information must be entered here.)

B. Computer\HKEY_CLASSES_ROOT\TypeLib\{00062FFF-0000-0000-C000-000000000046}

C. Check your Outlook version.

2. Delete all data other than 9.5 if you're using Office 2013.

A. Office 2016 or later versions: 9.6

B. Office 2013 version: 9.5

C. Office 2010 version: 9.4

D. Office 2010 version: 9.3

3. Leave only the version of Office you are currently using and delete the rest.

4. Restart Outlook.