Hello Weaver,
I already mentioned it in my first post.
all values in column C, that are selected, need to be the same
Sub test()
With Intersect(Selection, Range("C:C"))
If Application.CountIf(.Cells, .Cells(1, 1)) = .Cells.Count Then
MsgBox "All values in selection are equal"
Else
MsgBox "All values in selection are NOT equal"
End If
End With
End Sub