Search function works in OWA but not OUTLOOK

John W 1 Reputation point

Migrated several hundred users from exchange 2016 backend to exchange 2019.
Only a handful of users have experienced this search issue.

1) Search from OWA works normal no issues.

2) Search from Outlook thick client (2016 or 2019/365 office) only returns partial results.

Lets say I search for any e-mail from "Joe Average".
E-mail from current date back to 5/26/21 show up fine.
E-mail prior to January 2021 show up fine.
So anything between January and 5/26 do not show up in the search.
However if we scroll down in the inbox back a few months we can manually find it.

Tried to rebuild the index on the thick client.
Tried logging into another desktop, also a laptop, and also a VM. With different versions of office.
Tried moving from one 2019 database to another database.

Search works fine for my mailbox and for others. Only a handful of users out of 500 have reported the issue. Any ideas? Thanks!

Exchange Server Management
Exchange Server Management
Exchange Server: A family of Microsoft client/server messaging and collaboration software.Management: The act or process of organizing, handling, directing or controlling something.
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  1. Eric Yin-MSFT 4,386 Reputation points

    Outlook in Cached mode uses LOCAL indexing for searches. Outlook in Online mode, or OWA, or ActiveSync all use Exchange's indexing service.
    Which mode are they using?
    You can also try the following method for one of the problematic users:
    Export his mailbox to pst file - create a new mailbox - Import the pst file to the new mailbox, then test Outlook search function for the new user.

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