If QuickFinder cannot locate any documents matching a user’s search query, a Not Found message is returned. This is sometimes called a failed search. When you enable the search expansion feature, QuickFinder directs failed searches to additional indexes that you create for use with expanded searches.
The best way to implement expanded searches is to create special indexes that are targeted to very specific purposes. For example, you might create an index dedicated to sales reports information, which could help users who are trying to pinpoint sales reports for specific fiscal quarters. (For more information about how to create and manage indexes, see Section 8.5, Creating Indexes.)
To enable search expansion on a virtual search server:
On the Global Settings page of QuickFinder Server Manager, select a virtual search server from the Virtual Search Server List, then click Manage.
Under Settings, click Search.
Under Query Settings, click Yes next to Enable search expansion.
Click Edit next to the Default search expansion indexes and select the indexes to be used.
Click Apply, then click Apply Settings.