Coping with duplicates being created by code splitting worksheets into separate files

[snb]

I'd use:

Sub M_snb()
   c00="G:\OF\"

   sn = Filter(Split(CreateObject("wscript.shell").exec("cmd /c dir """ & c00 &"*.xls*"" /b/s").stdout.readall, vbCrLf), ".")
   
   For j = 0 To UBound(sn)
     With GetObject(sn(j))
       For Each sh In .Sheets
          sh.Copy
          With ActiveWorkbook
            .SaveAs Replace(Replace(sn(j), "\", "_"), ".xls", "_" & sh.Name & "_"), 51
            .Close 0
          End With
        Next
        .Close 0
      End With
    Next
End Sub