[Dovecot] Migrating from uw-imapd to dovecot

We recently switch from up-imapd to dovecot But many users are reporting that they cannot access certain mail folders.

The log file has: imap(dws): Sep 14 00:06:19 Error: File isn't in mbox format: /home/research/dws/mail/TaskDL

The files in the logs are "MBX mail folders", not "ASCII English text" as are the folders that can be read under Outlook.

Can anyone tell me how to fix this? This is a serious problem in switching.

I've read the FAQ and documentation but it doesn't speak to this specific problem.

Thanks in advance, Anne Hammond Tech-X Corporation