The Settings > MISCELLANEOUS > Search Index > Search Index tab controls whether and how files are indexed for use in performing searches.
Figure 129
Rebuild index every X hrs - Controls the frequency in which user/group virtual directories flagged for indexing are automatically re-indexed.
Update index upon file upload - If checked, file is automatically indexed upon upload.
Update index upon file rename - If checked, file is automatically re-indexed upon rename or deletion.
Update index upon user update - If checked, virtual directories for account are automatically indexed upon user account update.
Update index upon group update - If checked, virtual directories for group are automatically indexed upon group update.