Outlook 2007 from C# - COM exception, TYPE_E_LIBNOTREGISTERED

Question

I'm trying to make a program that would open new Outlook 2007 message.

I've referenced from COM tab Microsoft Outlook 12.0 ObjectLibrary.

These items showed up in references in VS:

Microsoft.Office.Core
Microsoft.Office.Inerop.Outlook

Now I try to invoke following code:

var _outlookInstance = new Microsoft.Office.Interop.Outlook.Application();
var _message = (OutlookApp.MailItem)_outlookInstance.CreateItem(OutlookApp.OlItemType.olMailItem);

where OutlookApp==Microsoft.Office.Interop.Outlook namespace.

While invoking second line of listing I keep getting this exception: (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 IID '{00063001-0000-0000-C000-000000000046}' failed due to the following error: Library unregistered. (Exception from HRESULT: 0x8002801D (TYPE_E_LIBNOTREGISTERED)).

That code worked well for Outlook 2003 on my other station.

I'll be grateful for any ideas how to solve it.

Answer 1

Office is not properly installed on that machine. You can verify that with Regedit.exe, navigate to HKEY_CLASSES_ROOT\Interface\{00063001-0000-0000-C000-000000000046}\TypeLib to verify the type library GUID (should be {00062FFF-0000-0000-C000-000000000046}), then to HKEY_CLASSES_ROOT\TypeLib\{00062FFF-0000-0000-C000-000000000046} to verify that the type library is indeed properly registered, using the correct type library version number. The latter part should be the problem.

If the target machine runs a 64-bit version of Windows, try setting the Project + Properties, Build, Platform Target to x86.