I keep having these errors with latest dapper. In my case dovecot is running on a 32-bit system, not 64bit. But mails arrive on a postfix server running on an amd64 box that NFS-mounts the user accounts containing Maildir's and drops files in there.
-- Corrupted index cache file errors on 64bit systems https://launchpad.net/bugs/33457 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
