Lost email history, folders and accounts with outlook upgrade Version 16.103 (25110922)

Hi Scott McKay
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Updated November 24th, 2025.
*Scott reversed back to legacy Outlook as the new Outlook for Mac did not display his other emails.

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Based on your description, may I know if you could provide a screenshot of how does it look like?
If your emails were stored in the cloud (for example, in an Exchange, Microsoft 365, or IMAP account), they should still be available because they sync from the server. It’s very unlikely that these emails would disappear after an update. However, if your emails were saved under the “On My Computer” section in Legacy Outlook, those messages were stored locally on your Mac and do not sync to the cloud. In that case, they can only be recovered from the local Outlook database or a backup (such as Time Machine).
You could also search for this directory for Outlook data file: ~\Library\Group Containers\UBF8T346G9.Office\Outlook\Outlook 15 Profiles then copy it to another place.

After that, please click on this link: https://learn.microsoft.com/en-us/officeupdates/update-history-office-for-mac#release-history-for-office-for-mac to download older version of Outlook (such as 16.101 or 16.102) and install again > after that you could copy this folder again to the location above.
If you would like to be supported, I'd strongly recommend to raise the support ticket within Outlook for assistance as I could not contact you via phone call to provide the suggestions. If you are the Global Administrator of the business account, you could also try to call Microsoft Support customer phone number: https://support.microsoft.com/en-us/topic/customer-service-phone-numbers-c0389ade-5640-e588-8b0e-28de8afeb3f2
I will send you a private message to check this with you and you could share with me any screenshots from your end.

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