If enabled, the Use Search History and Only Search New or Modified Files setting enables you to increase the speed and performance of Identity Finder's search by skipping any files already searched by Identity Finder that have not been modified since your previous search.
The first time you run a search after you enable this checkbox, a search history database will be created with information about all of files that Identity Finder searches. Each additional time you run a search with this checkbox enabled, Identity Finder will skip all files that have not changed since the previous search as long as they did not contain any Identity Matches. Files found to contain Identity Matches during a search will be searched again on later searches unless you specifically add those files to the Ignore Identities and Locations list.
If you modify your AnyFind settings or Include Unique Identities then you should Delete your database to ensure that all Files are searched again and a new database is created. Additionally, if you use the Hidden Web Data features of your web browser and new items are added, your unchanged Files will not be searched for this new information unless you delete your databases. Therefore, to always ensure maximum comprehensiveness, you should delete your database on the noted occasions.
To view or change these settings, click the Settings button on the Tools and Options ribbon.