[tfjern]

Thanks, Kinook, for the detailed and reasonably clear instructions.

After 1) performing an advanced search of URL matches wildcard *.pdf, 2) selecting all search results (1027 items selected), and 3) opening the Item Keywords dialog (Item | Keywords), all I get in Auto-generated keywords is one pdf (one count). That's it.

Then why is the file so large? I guess I will take your advice and start over with a new database, and then re-link all these files. Bummer!