Export to outlook Data file, “an unknown error occurred”

Kyle DM 0 Reputation points
2026-09-16T09:08:24.08+00:00

I need to export the emails into PST. However, when i create file, it keep appear "an unknown error occurred". I tried to uninstall and intall the latest version from microsoft store, the same problem still there.

Snipaste_2026-09-16_17-06-48

Microsoft 365 and Office | Install, redeem, activate | For home | Other

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  1. Chloe-V 13,360 Reputation points Microsoft External Staff Moderator
    2026-09-17T02:10:49.96+00:00

    Hi @Kyle DM

    I’m sorry the export still fails after reinstalling Outlook and trying a short local path.

    Since the screenshot appears to be from new Outlook, please try exporting from classic Outlook as a workaround:

    • Switch to classic Outlook.
    • Select File > Open & Export > Import/Export.
    • Choose Export to a file > Outlook Data File (.pst).
    • Select the mailbox or a small test folder, enable Include subfolders, and export it using a new file name.

    Microsoft documents separate export procedures for new Outlook and classic Outlook. Classic Outlook exports through the Import/Export wizard, while new Outlook uses Settings > Files > Export. Export emails, contacts, and calendar items to Outlook using a .pst file

    If a small folder exports successfully in classic Outlook, the mailbox data is likely accessible and the issue is limited to the new Outlook export process. If classic Outlook also fails, please create a new Outlook profile from Control Panel > Mail > Show Profiles > Add, add the account, allow synchronization to finish, and test the export again. Creating a new profile is a documented resolution for Outlook problems associated with a damaged profile. Terminated in error found in Outlook Sync Issues log files

    Please feel free to let me know if you have any further updates, thanks.

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