Highlighting Duplicate Data Using Two Cells

Hello,

I am trying to set-up conditional formating based on data within two columns. I have attached an example that will hopefully explain things better.

I have two columns, for the benefit of this example, Column A holds computer names and Column D holds dates.
I want to highlight any duplications in Column A (computer names) if the cell in Column D (same row) is empty. Once enter a date in that empty cell the highlighting for the duplication in Column A is removed.

I have tried several formulas but just can't get it right

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I have tried the brackets in different lcoations within the forumlas and I've also tried other varitaions (but don't have them listed to show)

This works for you?