When reactivating a unique index, IDXBUILD displays the following error message each time it encounters a duplicate index key. For example:

Fix RECID recid, table-name already exists with field-name value.

You must change the record data to eliminate duplicate keys to access all the data with this index. Use another index on the table (if one exists):

FOR EACH table-name USE-INDEX index-without-duplicate-keys:
UPDATE table-name.