A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data
Select D2:D1000 or however far you want. D2 should be the active cell in the selection.
Select these columns; I'll assume that the active cell is in column A.
On the Home tab of the ribbon, click Conditional Formatting > New Rule...
Select 'Use a formula to determine which cells to format'.
Enter the formula
=AND($D2<>"", COUNTIF($D$2:$D$1000, $D2)>1, $H2=FALSE)
Click Format...
Activate the Font tab.
Select red as text color.
Click OK, then click OK again.