Have a client with a borked Windows install who wants to get some mail out of his Outlook Express mail which I believe uses .mbox.
I'm looking for a decent program to do such a task.
it's unlikely that it is mbox. outlook express stopped using mbox-like (mbx) storage in the late 90s. assuming you can boot and install applications, thunderbird will import from outlook express.
if it is dbx, then you can use dbxconv to convert from dbx to mbox. from there you can import the mbox into your favorite email client.