Я успешно создал ISO-образ, но я получаю ошибки ввода-вывода «файл используется», пытаясь удалить файлы в rootFolderPath после возврата из вызова этого метода Create. Я пропускаю вызов Marshal.ReleaseComObject?

Спасибо,

ХО

/// <summary>
/// Create iso image from rootFolderPath and write to isoImageFilePath. Does not include the actual rootFolder itself
/// </summary>
public void Create()
{
    IFileSystemImage ifsi = new MsftFileSystemImage();
    try
    {
        ifsi.ChooseImageDefaultsForMediaType(IMAPI_MEDIA_PHYSICAL_TYPE.IMAPI_MEDIA_TYPE_DISK);
        ifsi.FileSystemsToCreate =
                FsiFileSystems.FsiFileSystemJoliet | FsiFileSystems.FsiFileSystemISO9660;
        ifsi.VolumeName = this.volumeName;
        ifsi.Root.AddTree(rootFolderPath, false);//use a valid folder
        //this will implement the Write method for the formatter
        IStream imagestream = ifsi.CreateResultImage().ImageStream;
        if (imagestream != null)
        {
            System.Runtime.InteropServices.ComTypes.STATSTG stat;
            imagestream.Stat(out stat, 0x01);
            IStream newStream;
            if (0 == SHCreateStreamOnFile(isoImageFilepath, 0x00001001, out newStream) && newStream != null)
            {
                IntPtr inBytes = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(long)));
                IntPtr outBytes = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(long)));
                try
                {
                    imagestream.CopyTo(newStream, stat.cbSize, inBytes, outBytes);
                    Marshal.ReleaseComObject(imagestream);
                    imagestream = null;
                    newStream.Commit(0);
                }
                finally
                {
                    Marshal.ReleaseComObject(newStream);
                    Marshal.FreeHGlobal(inBytes);
                    Marshal.FreeHGlobal(outBytes);
                    if (imagestream != null)
                        Marshal.ReleaseComObject(imagestream);
                }
            }
        }
    }
    finally
    {
        Marshal.ReleaseComObject(ifsi); 
    }
}