Outlook 2016 and MAPI

Question

Hello,

which versions of Outlook 2016 do support MAPI?

Answer 1

Outlook is built on top of Extended MAPI. So, all Outlook versions support Messaging API.

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Answer 2

But some of our customers (with presumably a "Click-To-Run" version of Outlook 2016) are reporting that the MAPI functions of our software don't work.

And according to this page, at least the "Click-To-Run" versions of Outlook 2010 didn't support MAPI:

https://support.microsoft.com/en-us/help/981242/some-applications-are-incompatible-with-a-click-to-run-installation-of-outlook-2010

Unfortunately I was not able to find a similar page with information about Outlook 2016.

Answer 3

You need to make sure you are loading the MAPI system correctly. Does MFCMAPI (of the appropriate bitness) run in their environment? If yes, see how MFCMAPI loads the MAPI system.

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Dmitry Streblechenko (MVP)
http://www.dimastr.com/redemption Redemption - what the Outlook Object Model should have been Version 5.5 is now available!

Answer 4

We are currently using "MAPIStubLibrary" (https://github.com/stephenegriffin/MAPIStubLibrary).

Is this deprecated?

Answer 5

That is what you need to be using. Are you running into a particular problem?

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Dmitry Streblechenko (MVP)
http://www.dimastr.com/redemption Redemption - what the Outlook Object Model should have been Version 5.5 is now available!

Answer 6

Yes, but its complicated. I try to explain what I found out after further investigating.

Our code calls this function sequence every time it sends a mail:

GetPrivateMAPI
MAPIInitialize
... lots of MAPI functions ...
MAPIUninitialize
UnLoadPrivateMAPI

The very first mail is sent without problems. For the second mail the program stops after "MAPIInitialize" with a message box that Outlook has to be repaired.

What happenes is that for the first mail "GetPrivateMAPI" returns "msmapi.dll". During the sequence "olmapi32.dll" is also loaded into the process space.
"UnLoadPrivateMAPI" then unloads "msmapi.dll", but "olmapi32.dll" does not get unloaded automatically.

So for the second mail "GetPrivateMAPI" returns "olmapi32.dll" and this seems to cause the problem.

The problem did not occur with older Outlook versions. I tested it for example with Outlook 2007. There "GetPrivateMAPI" returns "olmapi32.dll" already with the first mail.

As a workaround I now have moved the call to "UnLoadPrivateMAPI" to the ending of our program.

Answer 7

It is not a good idea to unload the MAPI system and then load it again. You'd be better off to always have it loaded until your app terminates.

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Dmitry Streblechenko (MVP)
http://www.dimastr.com/redemption Redemption - what the Outlook Object Model should have been Version 5.5 is now available!