The When Mask Matches is enabled, mask these Identity Types setting replaces your Matches (i.e., passwords or other Identity Types found by Identity Finder during a search) with asterisks, thereby hiding them from the results view. There are several reasons you might want to do this, but you should note it only affects the results view and not the Preview Pane. If you choose to Save your results, the actual identity matches will be written to the file, not the asterisks.
To view or change these settings, click the Settings button on the Tools and Options ribbon.