Appending the Message to a File Click MB1 on Append to Existing File to append the message to a file if a file with the same name already exists. If the message you want to extract contains a DDIF, DTIF or a nonstandard external file, you will not be able to append it to an existing file. If the file to which you want to append the message does not exist, it will be created. Additional topics: * Extract Dialog Box