Automatic migration of “On My Computer” folders from Legacy Outlook for Mac to New Outlook transfers only folders but not emails

Tsoumpas, C (ngmb) 55 Reputation points
2026-10-03T07:35:00.4533333+00:00

I am migrating “On My Computer” folders from Legacy Outlook for Mac to New Outlook. Legacy contains approximately 225,999 messages (~56 GB) and the complete folder hierarchy is intact. New Outlook creates the correct folder hierarchy and almost immediately reports that 225,999 messages were successfully imported, but all imported folders are empty and none of the messages can be found using Search. There is approximately 278 GB of free disk space. New Outlook then asks me to remove the Legacy folders because it considers the migration successful. I have NOT removed the Legacy data. I also have an OLM backup. How can I get my actual emails transferred succesfully?

Outlook | MacOS | New Outlook for Mac | For business
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  1. Jayden-P 3,130 Reputation points Independent Advisor
    2026-10-03T08:33:19.8266667+00:00

    Hi @Tsoumpas, C (ngmb)

    Just to confirm, in New Outlook, do the migrated folders appear under On My Computer but remain empty, and are all folders affected or only some of them?Since the emails are still accessible in Legacy Outlook and you have an OLM backup, you may try:

    1. Remove the previously migrated folders from New Outlook (only the migrated copy, not the original Legacy data).
    2. In Legacy Outlook, verify the OMC folders contain all expected messages.
    3. If needed, import the OLM into Legacy Outlook and confirm the contents are present.
    4. Switch to New Outlook and allow the automatic On My Computer migration to run again.

    Screenshot 2026-10-03 at 15.27.54.png

    Before proceeding, please keep both the original Legacy Outlook data and the OLM backup unchanged so that you have a recovery path if the migration does not complete as expected.

    If the migration continues to produce the same result after retrying, another workaround to consider would be:

    1. Convert the OLM file to a PST file using a third-party conversion tool.
    2. Import the PST into New Outlook.

    Disclaimer: Microsoft does not provide, support, or guarantee third-party OLM-to-PST conversion tools. Any such tool should be thoroughly evaluated by your organization before use. Please ensure that you fully understand the risks before using any third-party tool.

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