Public Sub TestCDO()
    'Microsoft CDO for Windows 2000 Library (cdosys.dll) should be referenced
    Dim Messages As CDO.IMessages
    Dim DD As New CDO.DropDirectory
    Dim Path As String
    
    'вариант 1 Path = "outlook:\\Все общие папки\....."
    'вариант 2 Path = "C:\Temp" или "C:\TEMP\"
    Set Messages = DD.GetMessages(Path)
    MsgBox Messages.Count
End Sub