Sub ki019()
fff = Application.GetOpenFilename(Title:="ファイル名指定")
erck = 0
On Error GoTo errcheck
Open fff For Binary Lock Read Write As #1
Close #1

If erck = 1 Then
   MsgBox fff & " は使用中です" & Chr(13) & _
           "後で再度起動してください。"
Else
    Workbooks.Open Filename:=fff
End If

Exit Sub
'
errcheck:
    erck = 1
    Resume Next
End Sub