Issues with applying IF function to Data Validation List

Hi all,

This is an edited version of something posted few days ago, but as this still needs to be solved I decided to give it another go with a more detailed explanation and a new attachment.

I'm having trouble applying an IF function to a Data Validation. Basically, I want a list under Column D to only become available if "Missed" is selected from the drop-down list in Column C.

The attached document is a replica of the actual document I'm using. Unfortunately I cannot share the original one with you as it contains confidential information, however the structure, layout, formulae, and conditional formatting, are identical in both documents.

As you will note, I have managed to successfully apply this approach to Column E, using the following formula: =IF($C8="Missed",Lists!$J$11:$J$13,"")

However, when I try to apply a similar formula to Column D, =IF($C8="Missed",Lists!$H$2:$H$13,"")) I get the following message: "The list source must be a delimited list, or a reference to single row or column".

Can anyone advise on what may be causing this and, more importantly, how to resolve it?

Many thanks in advance!
G

p.s: very annoyingly, a colleague just pointed out that the formula actually does work in the Test version I have attached, but it does not work in the original document. That said, we have both gone over both documents over and over and can't identify anything that would explain why it works on one but not the other, as they are both identical in structure, layout, formulae, and conditional formatting.

I can not tell you why data validation is accepting the IF based formula for E8 as I get the "The list source must be a delimited list, or a reference to single row or column" when I attempt to close it using OK.
What I may be able to help with is to get a drop down in D8:
1. Select List!H2:H13 and name that range MissedD
2. Select Prog. Milestones D8 and use the following as the source for the data validation list: =INDIRECT(C8&"D")
When either Done or On Track are selected in C8 the drop down will not open, or display a blank as I assume you want.
When Missed is selected in C8 the drop down will display the dates from List!H2:H13
Let us know if you have any questions.

You're Welcome. Thank You for the feedback and for marking the thread as 'Solved'. I hope that you have a blessed day.