If you have trouble integrating applications with GroupWise MAPI, try the workaround described in this section.
When gwmailto.exe is registered, it intercepts the following three simple MAPI functions:
MAPILogoff
MAPILogon
MAPISendMail
If you use MAPILogon, gwmailto.exe returns an invalid MAPI session handle. Any applications that call MAPILogon while gwmailto.exe is registered as the default mail client cannot call extended MAPI features.
To workaround this issue, use one of the following two workarounds:
Call MAPILogonEx rather than MAPILogon.
Because MAPILogonEx is not intercepted by gwmailto, MAPILogonEx is processed through the normal route of the message store provides that is configured in the MAPI profile.
Uninstall gwmailto (which is listed as GroupWise Internet Browser Mail Integration in your Control Panel's list of software).
IMPORTANT:Uninstalling gwmailto prevents any “mailto:” links from working correctly in your Internet browser.