Search results returned by Microsoft Outlook are limited to 250 items by default, allowing for speedy searches.
The limit can be easily increased to either 1000 or unlimited results. The unlimited option requires editing a registry key (more advanced).
These settings have been tested on Outlook (Classic mode), version 365 and 2024 LTSC. Other platforms are not supported. The "New" version of included with Office 365 handles search results differently.
To increase search results limit to 1000:
In Outlook, click the File menu -> Options
Select Search in the left column.
Locate and clear the selection for: “Improve search speed by limiting the number of results shown”
Additionally, if more results above 1000 are desired, a registry key edit can be used to increase the number of results to unlimited (more advanced option). Please note, this may cause Outlook to momentarily "freeze" while a search is ongoing.
If you are uncertain how to edit registry key: STOP. Improper editing of the registry can cause serious issues and may prevent Windows from operating and carries the possibility of losing data and files. Please contact the UW IT Help Desk for assistance.
Open the Registry Editor and modify/create the value:
HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Search\DisableServerAssistedSearch
REG_DWORD = 0x01