Tracking Down Invalid References

Joel noted that when he closes a workbook that has thousands of formulas in it he is getting this message lately: "A formula in this worksheet contains one or more invalid references." Joel wonders how he can know which of the seven worksheets in this workbook is being referred to. How can I find the errant formula? I do not observe any problems in the display of information on my reports.

Tracking down invalid references can be frustrating. There are several places you can start to look. The first is in the formulas that are on the worksheets. (Yes, you need to do these steps for each worksheet in the workbook.) Use the Go To Special dialog box (press F5 and choose Special) to choose to go to only the cells that contain errors. You can then use the Tab key to move amongst any cells that Excel selects.

You could also use the Find tool to look for possible errors. Just press Ctrl+F to display the Find tab of the Find and Replace dialog box, then search for the # character. Make sure you tell Excel to do its searching within Formulas. Inspect anything that is found to see if it is an error or not.

You should also take a look at any named ranges defined in your workbook. Look at each name in the Define dialog box (Insert | Name | Define), making sure that whatever is in the Refers To box doesn't include any error indications.

These aren't all the places that there could be errors; Excel is really good at letting errors exist in lots of places. If you need to search for errors often, you might try a macro that looks through your formulas for any potential errors.

Sub CheckReferences()
' Check for possible missing or erroneous links in
' formulas and list possible errors in a summary sheet

  Dim iSh As Integer
  Dim sShName As String
  Dim sht As Worksheet
  Dim c As Cell
  Dim sChar As String
  Dim rng As Range
  Dim i As Integer, j As Integer
  Dim wks As Worksheet
  Dim sChr As String, addr As String
  Dim sFormula As String, scVal As String
  Dim lNewRow As Long
  Dim vHeaders

  vHeaders = Array("Sheet Name", "Cell", "Cell Value", "Formula")
  'check if 'Summary' worksheet is in workbook
  'and if so, delete it
  With Application
    .ScreenUpdating = False
    .DisplayAlerts = False
    .Calculation = xlCalculationManual
  End With

  For i = 1 To Worksheets.Count
    If Worksheets(i).Name = "Summary" Then
      Worksheets(i).Delete
    End If
  Next i

  iSh = Worksheets.Count

  'create a new summary sheet
    Sheets.Add After:=Sheets(iSh)
    Sheets(Sheets.Count).Name = "Summary"
  With Sheets("Summary")
    Range("A1:D1") = vHeaders
  End With
  lNewRow = 2

  ' this will not work if the sheet is protected,
  ' assume that sheet should not be changed; so ignore it
  On Error Resume Next

  For i = 1 To iSh
    sShName = Worksheets(i).Name
    Application.Goto Sheets(sShName).Cells(1, 1)
    Set rng = Cells.SpecialCells(xlCellTypeFormulas, 23)

    For Each c In rng
      addr = c.Address
      sFormula = c.Formula
      scVal = c.Text

      For j = 1 To Len(c.Formula)
        sChr = Mid(c.Formula, j, 1)

        If sChr = "[" Or sChr = "!" Or _
          IsError(c) Then
          'write values to summary sheet
          With Sheets("Summary")
            .Cells(lNewRow, 1) = sShName
            .Cells(lNewRow, 2) = addr
            .Cells(lNewRow, 3) = scVal
            .Cells(lNewRow, 4) = "'" & sFormula
          End With
          lNewRow = lNewRow + 1
          Exit For
        End If
      Next j
    Next c
  Next i

' housekeeping
  With Application
    .ScreenUpdating = True
    .DisplayAlerts = True
    .Calculation = xlCalculationAutomatic
  End With

  Set wks = Nothing
  Set sht = Nothing
  Set rng = Nothing

' tidy up
  Sheets("Summary").Select
  Columns("A:D").EntireColumn.AutoFit
  Range("A1:D1").Font.Bold = True
  Range("A2").Select
End Sub

This macro creates a worksheet called "Summary" that is used to list information about any errors detected in the worksheet links.

You can also use Excel MVP Bill Manville's FindLink program, which does an amazing job of locating information in links. You could use the add-in to search for the # character in all your links, which should help you locate the errors. More information on FindLink can be found here:

http://www.manville.org.uk/software/findlink.htm

ExcelTips is your source for cost-effective Microsoft Excel training. This tip (8662) applies to Microsoft Excel 97, 2000, 2002, and 2003. You can find a version of this tip for the ribbon interface of Excel (Excel 2007 and later) here: Tracking Down Invalid References.