In short, I migrated to a new server (32 bit FreeBSD to 64 bit Debian) and some (all?) users who open their main inbox (stored in /var/spool/mail) using Open Webmail are finding that their previously read messages have vanished. I think they may not vanish until the first new message arrives and then the user tries to reaccess the inbox.

I'm not certain the problem is exclusive to open webmail, but it probably is... I HOPE.

If anyone has any idea how I might track this problem down (assuming no one has direct knowledge of the problem), I'd appreciate it. I'm pretty much lost.

EDIT

The problem may have to do with differences in the mailbox format. Or it may have been due to a locked file being copied when I used rsync to copy the /var/spool/mail directory from server to the other. I'm hoping it's the second problem as that would be limited in scope.

For the record: a fresh and up to date OWM installation has a global configuration setting that, by default, forces all read messages to be moved from the user mail spool (inbox) into saved-messages.

To fix, find the OWM configuration (in this case linked from /etc/openwebmail/openwebmail.conf ) and disable this feature.