This article explains the BACKTRACK error message “Item Column: Must have non-unique records” and details how to fix the underlying problem that caused it to appear.
When performing a add/move/delete to a record on BACKTRACK, the error message: “Item Column: Must have non-unique records” appears. This error message indicates that there are more than one or more records in the database that contain the same unique identification number or key field.
The best way to fix this problem is to use SQL management studio, run a query on your database, determine which record(s) contain the same identification number, and delete the undesired record.
SQL solution procedure:
Run SQL management studio > connect to your database > create a new query > input the following:
SELECT YourColumn, COUNT(*) TotalCount
GROUP BY YourColumn
HAVING COUNT(*) > 1
ORDER BY COUNT(*) DESC
Execute the query > select the entire row of the undesired record > right click and delete the record.
Error messages first appeared: BACKTRACK 2012.00.02