Sheets("Sheet1").range("A:DD").Interior.ColorIndex = 6 -> That won't work unless the entire range shares the same color. What you are going to have to do, is either check each cell individually OR come up with an alternative (like below).


1)
Question - how are you finding the cells to turn yellow in the first place? - You could a named formula to remember that range (call it required_cells or something).
Then your final check will be much easier as you can just check that range - still one cell at a time, but you will greatly reduce the number of cells to check.

2)
Use some kind of special cell to hold the number of required cells (like off to the side, call it 'RequiredCount' or something). 'RequiredCount' will hold a value, say 10 for example. Use another cell, call it 'CountActual' to hold something like =COUNTA(A1, B3, Y7...) where those made up addresses are the actual references to the required cells (you'll have to populate these special cells when you make the required cells yellow).

IF those 2 cells don't equal each other - there is missing information from one or more required cells... Have your before save macro just check the numbers.

Make sense?