Overview
The Messaging API is a COM-like API that provides access to the contents of messaging stores. CDO 1.2.1 (Collaboration Data Objects, version 1.2.1) is a package providing access to Outlook-compatible objects through a COM-based API. Using either CDO or MAPI, a program can connect to a MAPI store, and then perform operations against that store. Starting with Exchange 2007, Microsoft will distribute the MAPI client libraries and CDO 1.2.1 as a Web download.
System Requirements
- Supported Operating Systems: Windows Server 2003; Windows Server 2008; Windows Vista; Windows XP
- This package will not install on a system on which any version of Microsoft Outlook or Microsoft Exchange Server 2003 or earlier is installed.
This download is available here.


First of all thanks for this thread
OK, thats fine what should i do if i have outlook installed in vista OS ????.
I’m trying to send email throw VB.NET 1.1, i tryed Web.Mail.MailMessage and it keep giving CDO.Message errors ???
Please help me by code or give a URL could help.
Thanks all.
Should be fine now. Sorry about that.
It seems like the Download URL does not work!