Mark,
My users are used car dealers who have somewhat less than excellent computer skill by and large. They ( like other users ) do all kinds of crazy things that I have no control over. They have been using Fox DOS for several years. The worst thing they could do there was lose a table or two which was generally easily restored. The fact that the DBC will not open under certain conditions and that if a table's indexes are missing it will not allow you to open the table to fix it are somewhat scary to me because of the support issues involved. My observation is that if the DBC and SDT get out of syn it is like a dog chasing its tail. Is the only solution then to ship out or install an entire new set of DBC and SDT files and then run update()? What did you do when this happened to you?