Most commonly, particularly when the file is received from others, the problem is that the file is not really a transport file, but, rather, is another kind of system file. You should examine the first part of the file, either in an editor or by simply typing it to the screen. The text “HEADER RECORD*********LIBRARY HEADER RECORD” should appear at the beginning of the file. If it does not, it is not a transport file. You should refer to the Stat/Transfer manual or SAS’s documentation to find out how to create a transport file in SAS.