I moved my /var/mail partition to a different disk drive

by:
    creating a new ext4 partition
    mounting it as /newvarmail
    copying the contents of the old /var/mail partition to it
    unmounting both the old and new mail partitions
    updating the /etc/fstab entry by
        chainging the partition name
    changing the file system to ext4 from ext3
    mounting the new one as /ver/mail
Everything seems to work smoothly except for one thing:
    When I read a new message in mutt, the 'N' indicaating it is new does not disappear after reading it.

(And one time only, mutt mentioned that the mail file was read-only.)

ls tells me
-rw------- 1 hendrik mail 102495117 May 20 08:06 hendrik
and for the old var/mail, it tells me
-rw------- 1 hendrik mail 102369929 May 20 07:34 /oldvarmail/hendrik

much the same except that I seem to have received some more mail.

-- hendrik