After reboot dovecot service need a restart. dovecot service starts as S99dovecot with only S99rc-local coming up.
After boot following error is filled up in dovecot.log
Aug 28 11:33:12 imap(vuser): Error: open(/home/fetchmail/mailroot/map/dovecot.index.log) failed: Permission denied (euid=500(vuser) egid=500(vuser) missing +r perm: /home/fetchmail/mailroot/map/dovecot.index.log, euid is not dir owner) Aug 28 11:33:12 imap(vuser): Error: file_dotlock_create(/home/fetchmail/mailroot/map/dovecot-uidlist) failed: Permission denied (euid=500(fetchmail) egid=500(fetchmail) missing +w perm: /home/fetchmail/mailroot/map, euid is not dir owner) Aug 28 11:33:12 imap(vuser): Error: open(/home/fetchmail/mailroot/map/dovecot-uidlist) failed: Permission denied
After Linux has booted you just issue service dovecot restart
And everything is back to normal and no error.
Running on a Pentium 800MHz not too fast pc