Since a Catalog database is not linked to any particular volume, there is a limit to the abilities of the Update Index command. When Update Database for Selected is selected from the Browser menu in a Catalog, Pro Tools searches for the items represented by the aliases in the Catalog and updates the following information:Metadata for all files found online, including File comments, are updated.Database Comments are not updated, because they are unique to each Catalog and are not part of the file’s metadata.