Welcome to the forum Sergio,

If you use this formula in a spare column on the latest workbook =COUNTIF([Book1]Sheet1!$A$1:$A$400,A1) and copy down you will get a bunch of 1's (when the names exists on both files), and 0's when the name is NOT on the older file.

Just set up a data filter on ZERO, and those are the names to ADD to your list.

If you do the same on the OLDER file - the 0's will be the list of names to delete.

I hope this helps, please let me know!

Regards,

David

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