MAPI of Outlook 2019 does not perform as well as Outlook 2010

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We are working on an archival solution. We have Microsoft Exchange as one of the supported sources from which documents are archived to a storage repository. Our application requires Outlook to be installed on the same server and uses MAPI for communication with the Exchange Server (On-Premises). We have a couple of queries related to MAPI:


  1. We ran a performance test with our application along with Outlook 2010 vs Outlook 2019, both connected to an on-prem Exchange 2016 Server. We saw that the rate of archival when using Outlook 2010 client was 74.9 mails/min and when used with Outlook 2019 was only 36.5 mails/min. The environment details in both were the same except for the outlook client used. Since the MAPI dlls are provided by the Outlook Client, we wanted to know if there are any differences in MAPI of Outlook 2010 vs Outlook 2019 that could manifest as this performance difference?
  2. We have tried using the MFCMAPI tool to compute some time durations for operations like "Display Attachment Table" and "Display Recipient Table". Attaching a spreadsheet with our results. Please note that we have used Debug flag 0x40000000 to only list the MAPIFunctions in MFCMAPI tool and Execution time calculated as the difference in Timestamps between first call OpenProperty and last call QueryRows. Is there any way workaround/circumvention for improving the response time in Outlook 2019?
  3. Are there any particular debugging tools that can be used to further diagnose the performance difference?

Any suggestions/pointers on the above would be highly appreciated!



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