Sub linkupdate()
    Application.DisplayAlerts = False
    Dim osld As Slide
    Dim oshp As Shape
    For Each osld In ActivePresentation.Slides
        osld.Select
        For Each oshp In osld.Shapes
            If oshp.Type = msoLinkedOLEObject Then
                oshp.Select
                oshp.LinkFormat.Update
            End If
        Next oshp
    Next osld
    Application.DisplayAlerts = True
End Sub