Some emails missing when search in Outlook 365

Question

Hello,

we have Exchange 2016 DAG, some users are complaining about missing emails once they search in Outlook. However email is present in the inbox but once search doesn't appears in the list.

Please note : it happen for some emails only and random emails not related to any particular date or duration, most of the emails appears but some are missing.

Thanks

Answer 1

Hi @IT Engineer ,

Please try changing the search scope to "Subfolders" or "All Outlook Items" and see if the missing mails can appear in the search results:

If this works, it's likely to be related to the FAST Search and you can then add the following registry keys to disable it:
(Important: Follow the steps in this section carefully. Serious problems might occur if you modify the registry incorrectly. Before you modify it, back up the registry for restoration in case problems occur.)

1. In Windows, right-click Start, and then select Run. In the Open: box type regedit, and then click OK. This will open the registry editor.
2. In the registry editor dialog box, find this subkey in the registry, and then click it:
   • HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Search
3. Click Edit > New > DWORD Value.
4. Type DisableServerAssistedSearch for the name of the DWORD, and then press Enter.
5. Right-click DisableServerAssistedSearch, and then click Modify.
6. In the Value data box, type 1 to enable the registry entry, and then click OK.
7. Close the registry editor, and then restart Windows.

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