This file points out some reasons that you might want to switch frommbox format to a new format, maildir.1. The trouble with mboxThe mbox format---the format of ~user/Mailbox, understood by BSD Mailand lots of other MUAs---is inherently unreliable.Think about it: what happens if the system crashes while a program isappending a new message to ~user/Mailbox? The message will be truncated.Even worse, if it was truncated in the middle of a line, it will end upbeing merged with the next message! Sure, the mailer understands that itwasn't successful, so it'll try delivering the message again later, butit can't fix your corrupted mbox.Other formats, such as mh folders, are just as unreliable.qmail supports maildir, a crashproof format for incoming mail messages.maildir is fast and easy for MUAs to use. Even better, maildir workswonders over NFS---see below.I don't want to cram maildir down people's throats, so it's not thedefault. Nevertheless, I encourage you to start asking for maildirversions of your favorite MUAs, and to switch over to maildir as soon asyou can.2. Sun's Network F_ail_u_re SystemAnyone who tells you that mail can be safely delivered in mbox formatover NFS is pulling your leg---as explained above, mbox format isinherently unreliable even on a single machine.Anyway, NFS is the most unreliable computing environment ever invented,and qmail doesn't even pretend to support mbox over NFS.You should switch to maildir, which works fine over NFS without anylocking. You can safely read your mail over NFS if it's in maildirformat. Any number of machines can deliver mail to you at the same time.(On the other hand, for efficiency, it's better to get NFS out of thepicture---your mail should be delivered on the server that contains yourhome directory.)Here's how to set up qmail to use maildir for your incoming mail:   % maildirmake $HOME/Maildir   % echo ./Maildir/ > ~/.qmailMake sure you include the trailing slash on Maildir/.The system administrator can set up Maildir as the default for everybodyby creating a maildir in the new-user template directory and replacing./Mailbox with ./Maildir/ in /var/qmail/rc.Until your MUA supports maildir, you'll probably want to convert maildirformat to (gaaack) mbox format. I've supplied a maildir2mbox utilitythat does the trick, along with some tiny qail and elq and pinq wrappersthat call maildir2mbox before calling Mail or elm or pine.