Hello! Win 7 64 bit+ Civil 3D 2010. When one dwg drawing has been opened in Civil, and later in Windows Explorer I has clicked twice at another one dwg file, I got a message with text "Error writing file acad.cuix" (my translation from Russian "ошибка записи файла acad.cuix") and with ok button only. Can I open second file at the same time without such error?