Pat,
>We are seeing 10-15 records a day failing the LOCATE when they later need to be edited. We know the records were not deleted, an INDEXSEEK on a unique field returns .t., and a manual SEEK places the cursor on record in the table that doesn't match the SEEK criteria. This seems to indicat that a record appears to be in the index but not in the table.
This sounds like you have a corrupted CDX file. You need to rebuild it.