title: VBA - ActiveCell.Interior.ColorIndex -4142 error by conditional formatting
body: <p>I have a check which ensures that no cells in a row are filled with Red(colorindex 3) before carrying on with the function however the Interior.ColorIndex is weirdly returning '-4142'. Anyone experienced this before/notice an error in my code?</p>
  
  <pre><code>If UCase(ActiveCell.Offset(0, -1).Value) = "X" Then
  
    For i = 0 To 7
      If ActiveCell.Offset(0, i).Interior.ColorIndex = 3 Then
          MsgBox "Correct fields highlighted in red."
          Exit Sub
  
      End If
     Next
      ident = ActiveCell.Value
      verNo = ActiveCell.Offset(0, 1).Value
      title = ActiveCell.Offset(0, 2).Value
      status = ActiveCell.Offset(0, 3).Value
      location = ActiveCell.Offset(0, 4).Value
      appDate = ActiveCell.Offset(0, 6).Value
      ccRef = ActiveCell.Offset(0, 7).Value
  </code></pre>
  
  <p>Where I initially add the highlighting:</p>
  
  <pre><code>With ThisWorkbook.Worksheets("Document Index").Range("B5:B500")
      .FormatConditions.Delete
      .FormatConditions.Add Type:=xlExpression, Formula1:="=AND(($B5=""""), 
  $A5=""X"")"
      .FormatConditions(1).Interior.ColorIndex = 3
      .FormatConditions.Add Type:=xlExpression, Formula1:="=AND(($B5&lt;&gt;""""), 
  $A5=""X"")"
     .FormatConditions(2).Interior.ColorIndex = 37
  End With
  </code></pre>