If cell = 'YES', cell directly to the left is required

[chubert]

Hi everyone, need some help with how to accomplish ensuring cells are populated when required.

Whenever any cell under Column 'ANSWER' = 'YES', cell to the left (under Column 'Question') must be populated.
Directly after entering YES into the Answer column, if cell to the left is not populated, a message should appear 'Question cannot be empty if Answer = 'Yes''.

Any help greatly appreciated!

Question	Answer
<must be populated>	YES
<does not need to be populated>	NO
<must be populated>	YES

 

[JLGWhiz]

The columns we are working with are not specified in the OP, so you will need to correct them in the code if they are not columns A and B.
This is worksheet event code and must be installed in the the worksheet code module. If you already have a worksheet_change macro installed, then this will need to be merged into the existing one.

Private Sub Worksheet_Change(ByVal Target As Range)
If Target.Cells.Count > 1 Then Exit Sub
Application.EnableEvents = False
If Not Intersect(Target, Range("B:B") Is Nothing Then
    If Target.Value = "Yes" And Target.Offset(, -1) = "" Then
        Application.Undo
        MsgBox "Cells under 'Question' must be populated to answer 'Yes'"", vbExclamation, "INVALID ENTRY"
   End If
End If
Application.EnableEvents = True
End Sub