>>I've never seen tags just disappear. Perhaps someone restored an old cdx. LOCATE and SQL will operate without the tags. SEEK won't.
>
>Me neither. Impossible that an old .cdx was restored - there has never been one (until now) that has less than 8 tags. The table is open pretty much 24/7 so restoring an old .cdx or running DELETE TAG etc. would be pretty much impossible.

Just an idea... perhaps the cdx was thoroughly screwed, and the info on all tags was lost. The info on PK is stored in the dbc, so that one was rebuilt. Which mechanism may do this is impossible to know. Don't know whether something would do validation/recover, whether that's covered with table checking on open, whether there's some mechanism in the app (Stonefield?)... just a WAG.