Here's my report about treating the output from: spamassassin --mbox alltests.txt >scanned.mbox
as an mbox file. In summary ---------- If you use SA to process a multi-message file with the --mbox option the output is an acceptable mbox file. Detail ------ After passing my standard regression test case through Spamassassin the result was successfully processed by my JavaMail/mstor based application. alltests.txt is an mbox format file containing 12 messages that illustrate a variety of test cases for my application. After this I ran my usual application stress test, which contains some 25,000 messages. SA processed these without any problems. The result ran through my repair program successfully. This replaces "undisclosed-recipients:" with a default e-mail address and also any ';' separators in a recipients list by ','. Both of these upset JavaMail, which has rather picky header parsing, hence the repair program. Following this the file was successfully run through the application. ==== Many thanks to all who helped me with advice. Martin