A user had a question about the number of search results Outlook displays initially:
I’m using Outlook and my search results only show 250 items. Why is this?
Outlook limits the number of results displayed in order to speed up the search results in cached Exchange mode. The limit is 250 in Outlook 2013 and Outlook 2016, but 200 in Outlook 2010 and 2007. To display additional results, click More at the bottom of the results list.
You can change the Search options to show all results or edit the registry to increase the number of results. To show all results, go to File, Options, Search and untick Improve search speed by limiting the number of results shown.
To increase (or decrease) the number for items initially displayed you can add the SearchResultsCap value to the registry.
Open regedit then browse to the following key (where xx is your version of Outlook). Add the SearchResultsCap DWORD with the new value then restart Outlook.
Decimal Value: number you want as your limit: 0 to 4294967295
Outlook Version numbers are as follows:
|Popular Name||Version Number|
Search Results in Online Archives
Office 365 Online archive mailboxes have a limit of 250 results. While you can use the SearchResultsCap registry value to reduce the results, you'll need to refine the search to keep the results under 250 or use OWA (which does not have a limit).