Emails lost when switching from MS Office Home & Business for mac 2024 to 2021 version

cy chang 0 Reputation points
2026-10-02T04:56:59.05+00:00

Hi,

I have purchased both the 2021 & 2024 versions of Office Home & Business for Mac. Because the 2024 version lost the export function, I decided to switch back to 2021 version. Before switching, I did backup the Group Container files (including the "UBF8T346G9.Office" folder.) After switching, however, in Outlook, all the recent emails (since Jul this yr) that I had moved to folders under the "On My Computer" tag disappeared. Copying the previously backed-up ""UBF8T346G9.Office" folder to replace the newer one did not help. Does anyone know whether it is possible to retrieve these lost emails? If yes, how? Many thx!

Computer: iMac M1; OS: Tahoe.

Outlook | MacOS | Legacy Outlook for Mac | For home

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  1. Arshad Hussain 5 Reputation points
    2026-10-02T05:07:21.99+00:00

    Hi cy chang,

    I would first try to preserve and recover the old Outlook data before doing anything else.

    Try this first

    Close Outlook completely.

    Open Finder → Go → Go to Folder…

    Enter:

    ~/Library/Group Containers/

    Look for:

    UBF8T346G9.Office

    Do not delete or replace this folder. Since you already have a backup, make another copy of it somewhere safe.

    Open Outlook 2021 and check:

    View → Sidebar → On My Computer

    If the old folders are still missing, don't keep replacing the current UBF8T346G9.Office folder. The 2024 and 2021 Outlook versions may use different database/data structures.

    Check the old backup

    If your backup contains the older Outlook data, look inside:

    UBF8T346G9.Office

    for folders/files related to Outlook, Profiles, or Main Profile.

    If you find an old Outlook profile/database, keep the entire backup intact rather than copying individual files.

    If you have an .olm file

    This is much easier:

    Outlook → Tools/File → Import → Outlook for Mac archive (.olm)

    Then select the .olm file and import it.

    Important

    Don't uninstall/reinstall Outlook or delete the existing UBF8T346G9.Office folder yet. The missing emails may still be recoverable from the old 2024 data.

    Thanks

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