Yes, it is correct that these users' Inboxes are not available. If I try to open them with Outlook then I get the message "Cannot display the folder. The Inbox folder cannot be found."
But Outlook is able to display the calendars, and it is only the calendars that I am interested in.
Here is what I experience with MFCMAPI:
MDB - Open other mailboxes - From GAL, and setting option bits to 0x0000000C
This displays a dialog with the person's name on the title bar and "Root Container" in the left column. (The fact that it displays "Root Container" - is that significant? On the systems where things are working as expected MFCMAPI ususally displays the person's name in the left column.)
MDB - Display - Receive folder table
This displays a dialog with four lines: no message class, "IPC", "IPM" and "REPORT.IPM".
When I click on the IPM line it displays six properties in the lower half of the dialog, the first of which is marked with the error icon. But that's typical, isn't it?
Does this clarify things at all?
My knowledge of MAPI is rather limited. My policy is usually "if Outlook can do it, then MFCMAPI should be able to do it, and if MFCMAPI can do it, then my program should be able to do it." But right now the first part of that policy is not working.
Thanks again for your time.