This example displays the file name of each subdocument in the active document. The example also displays a message for each subdocument that hasn't been saved.
For Each subdoc In ActiveDocument.Subdocuments
subdoc.Range.Select
If subdoc.HasFile = True Then
MsgBox subdoc.Path & Application.PathSeparator _
& subdoc.Name
Else
MsgBox "This subdocument has not been saved."
End If
Next subdoc