To manually create a "legal blackline", follow these steps:

The following Word 2010 macro creates a blackline version from the existing document (the new document) and a selected document (which you will be prompted for). 

Note that you should add the following registry entry to resolve a Word bug concerning large table comparison: 

[HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Word\Options] "DocCompareLargeTables"=dword:00000001

Sub LegalBlackLine()

' Creates a Legal Blackline document from the current

' open document, and a selected previous version of the document.

' By Edward Chan (c) 2014

    Dim fOpen As FileDialog

    Dim OriginalDocument As String

    Dim RevisedDocument As String

    Dim ComparedDocument As Document

    RevisedDocument = ActiveDocument

    Set fOpen = Application.FileDialog(FileDialogType:=msoFileDialogOpen)

    fOpen.AllowMultiSelect = False  ' Don't allow multi-select.

    fOpen.Title = "Select the old version of the file"

    fOpen.InitialFileName = ActiveDocument.Path & "\Select Old File"

    If fOpen.Show = -1 Then  ' Selected a File

        OriginalDocument = fOpen.SelectedItems.Item(1)  ' Get the name of the Doc

    Else

    Exit Sub

    End If

    Documents.Open OriginalDocument, ReadOnly:=True

   Set ComparedDocument = Application.CompareDocuments( _

        OriginalDocument:=Documents(OriginalDocument), _

        RevisedDocument:=Documents(RevisedDocument), _

        Destination:=wdCompareDestinationNew, _

        Granularity:=wdGranularityWordLevel, _

        CompareFormatting:=False, _

        CompareCaseChanges:=False, _

        CompareWhitespace:=False, _

        CompareTables:=True, _

        CompareHeaders:=False, _

        CompareFootnotes:=True, _

        CompareTextboxes:=True, _

        CompareFields:=False, _

        CompareComments:=True, _

        CompareMoves:=True, _

        RevisedAuthor:="Changed to", _

        IgnoreAllComparisonWarnings:=False)

    Documents(OriginalDocument).Close

    Documents(ComparedDocument).Activate

'Change view to redline

    With Options

        .InsertedTextMark = wdInsertedTextMarkColorOnly

        .InsertedTextColor = wdBlue

        .DeletedTextMark = wdDeletedTextMarkStrikeThrough

        .DeletedTextColor = wdRed

        .RevisedPropertiesMark = wdRevisedPropertiesMarkNone

        .RevisedPropertiesColor = wdByAuthor

        .RevisedLinesMark = wdRevisedLinesMarkNone

        .CommentsColor = wdByAuthor

        .RevisionsBalloonPrintOrientation = wdBalloonPrintOrientationPreserve

    End With

    ActiveWindow.View.RevisionsMode = wdInLineRevisions

    With Options

        .MoveFromTextMark = wdMoveFromTextMarkHidden

        .MoveFromTextColor = wdAuto

        .MoveToTextMark = wdMoveToTextMarkColorOnly

        .MoveToTextColor = wdAuto

        .InsertedCellColor = wdCellColorNoHighlight

        .MergedCellColor = wdCellColorLightYellow

        .DeletedCellColor = wdCellColorPink

        .SplitCellColor = wdCellColorLightOrange

    End With

    With ActiveDocument

        .TrackMoves = True

        .TrackFormatting = True

    End With

End Sub

The following Word macro saves the current document as a PDF, with blackline markings on the left hand side for tracked changes.

'

' Show the blackline view and save as PDF.

' Edward Chan 2015-10-06

'

    With Options

        .InsertedTextMark = wdInsertedTextMarkNone

        .InsertedTextColor = wdRed

        .DeletedTextMark = wdDeletedTextMarkHidden

        .DeletedTextColor = wdByAuthor

        .RevisedPropertiesMark = wdRevisedPropertiesMarkNone

        .RevisedPropertiesColor = wdByAuthor

        .RevisedLinesMark = wdRevisedLinesMarkLeftBorder

        .RevisedLinesColor = wdAuto

        .CommentsColor = wdByAuthor

        .RevisionsBalloonPrintOrientation = wdBalloonPrintOrientationPreserve

    End With

    ActiveWindow.View.RevisionsMode = wdInLineRevisions

    With Options

        .MoveFromTextMark = wdMoveFromTextMarkHidden

        .MoveFromTextColor = wdAuto

        .MoveToTextMark = wdMoveToTextMarkNone

        .MoveToTextColor = wdAuto

        .InsertedCellColor = wdCellColorNoHighlight

        .MergedCellColor = wdCellColorLightYellow

        .DeletedCellColor = wdCellColorPink

        .SplitCellColor = wdCellColorLightOrange

    End With

    With ActiveDocument

        .TrackMoves = True

        .TrackFormatting = False

    End With

    ActiveDocument.ExportAsFixedFormat OutputFileName:= _

        Replace(ActiveDocument.FullName, ".docx", ".pdf"), _

        ExportFormat:=wdExportFormatPDF, OpenAfterExport:=True, OptimizeFor:= _

        wdExportOptimizeForPrint, Range:=wdExportAllDocument, From:=1, To:=1, _

        Item:=wdExportDocumentWithMarkup, IncludeDocProps:=True, KeepIRM:=True, _

        CreateBookmarks:=wdExportCreateHeadingBookmarks, DocStructureTags:=True, _

        BitmapMissingFonts:=True, UseISO19005_1:=False

End Sub

Redline and PDF

In a similar fashion, here is a macro that will create redlines and blue additions:

Note that you should add the following registry entry to resolve a Word bug concerning large table comparison: 

[HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Word\Options] "DocCompareLargeTables"=dword:00000001 

Sub RedLineAndPDF()

'

' Show the redline view and save as PDF.

' Edward Chan 2022-06-29

'

 Dim outputName As String

'Change view to redline

    With Options

        .InsertedTextMark = wdInsertedTextMarkColorOnly

        .InsertedTextColor = wdBlue

        .DeletedTextMark = wdDeletedTextMarkStrikeThrough

        .DeletedTextColor = wdRed

        .RevisedPropertiesMark = wdRevisedPropertiesMarkNone

        .RevisedPropertiesColor = wdByAuthor

        .RevisedLinesMark = wdRevisedLinesMarkNone

        .CommentsColor = wdByAuthor

        .RevisionsBalloonPrintOrientation = wdBalloonPrintOrientationPreserve

    End With

    ActiveWindow.View.RevisionsMode = wdInLineRevisions

    With Options

        .MoveFromTextMark = wdMoveFromTextMarkHidden

        .MoveFromTextColor = wdAuto

        .MoveToTextMark = wdMoveToTextMarkColorOnly

        .MoveToTextColor = wdAuto

        .InsertedCellColor = wdCellColorNoHighlight

        .MergedCellColor = wdCellColorLightYellow

        .DeletedCellColor = wdCellColorPink

        .SplitCellColor = wdCellColorLightOrange

    End With

    With ActiveDocument

        .TrackMoves = True

        .TrackFormatting = True

    End With

' Save doc

    ActiveDocument.ExportAsFixedFormat OutputFileName:= _

        Left(ActiveDocument.FullName, InStrRev(ActiveDocument.FullName, ".")) & "pdf", _

        ExportFormat:=wdExportFormatPDF, OpenAfterExport:=True, OptimizeFor:= _

        wdExportOptimizeForPrint, Range:=wdExportAllDocument, From:=1, To:=1, _

        Item:=wdExportDocumentWithMarkup, IncludeDocProps:=True, KeepIRM:=True, _

        CreateBookmarks:=wdExportCreateHeadingBookmarks, DocStructureTags:=True, _

        BitmapMissingFonts:=True, UseISO19005_1:=False

End Sub

Getting rid of Error! Reference Not Found

In Word, it is common to experience "Error! Reference Not Found" after accepting all changes. One of the common ways this happens is due to the way Track Changes allows you to either Accept or Reject a change.

When you create a field / heading, it is assigned an Original ID. You can then make a cross reference to this Original ID. But then someone else or Word makes a further change resulting in a New ID (such as renumbering or change to the ref). At this point Word needs to hold both the Original ID and the New ID (because it can't be sure if you'll reject the change or accept the change). Eventually you "Accept All Changes". At this point the reference breaks as the text is pointing to the Original ID that no longer exists. 

Here's a pictorial of this: