Confirmed: this is my "final" code regarding all the issues I posted on this thread. As a note, Tag1 is given by the user in a textbox:

Dim oSection As Section
Dim HdFt As HeaderFooter
Dim r, fnd As Range
Dim Tag1 as string

With ActiveDocument
            For Each oSection In .Sections
                For Each HdFt In oSection.Headers
                    With HdFt
                        DoEvents
                        If .LinkToPrevious = False Or oSection.Index = 1 Then
                            HdFt.Range.Select
                            
                            'Find 1st Tag
                            Set r = HdFt.Range
                            Set fnd = HdFt.Range
                            With fnd.Find
                                .Execute (Tag1)
                                If .Found = True Then
                                    TempStart = fnd.End
                                End If
                            End With
                            
                            'Do whatever else is required...

                        End if    
                    End With
                Next HdFt
            Next oSection
End With