I have linked an AEC Database to my drawing and I'm using to add keynotes to my drawing, using a multi-leader with an attributed block attached which displays the keynote number. Then to create my keynote legend I'm trying to use Data Extraction. when i get to the page in the dialog to be able to "Link external data" I run through motions and select me link and select the columns to match but when click "check match" it tells me "The data column in the external data does not contain unique values." But is does contain unique values. any ideas?