Function OpenWorkbook(Workbook_FullPath As String) As Workbook
On Error Resume Next
Workbooks(Dir$(Workbook_FullPath)).Activate
If Err <> 0 Then
Err.Clear
Workbooks.Open Workbook_FullPath
End If
Set OpenWorkbook = Workbooks(Dir$(Workbook_FullPath))
End Function
Sub Main()
Dim Wbk as Workbook
Wbk = OpenWorkbook(mon_Path + mon_Tableau(i))
Wbk.Sheets(1).Columns("A:A").Select
End Sub