printing - Cups won't start - Ask Ubuntu

i have ubuntu 16.04 has been perfect until now.

it has been printing since day 1 other day got error stupidly failed write down , didn't go @ /var/log/syslog.

the error cups directory gone missing. @ point had not been messing configuration, broke itself.

i thought rather me manually create whatever has gone missing, fix removing , re-installing software.

i removed , re-installed both hp's print software "hplip" , "cups". seems have wrecked cups completely. no longer starts.

below systemctl status output cups, before , after start command:

$ systemctl status cups   cups.service - cups scheduler    loaded: loaded (/lib/systemd/system/cups.service; enabled; vendor preset: enabled)    active: failed (result: exit-code) since sun 2016-11-06 10:06:50 gmt; 55min ago      docs: man:cupsd(8)   process: 1029 execstart=/usr/sbin/cupsd -l (code=exited, status=1/failure)  main pid: 1029 (code=exited, status=1/failure)  nov 06 10:06:50 vw-desk2 systemd[1]: started cups scheduler. nov 06 10:06:50 vw-desk2 systemd[1]: cups.service: main process exited, code=exited, status=1/failure nov 06 10:06:50 vw-desk2 systemd[1]: cups.service: unit entered failed state. nov 06 10:06:50 vw-desk2 systemd[1]: cups.service: failed result 'exit-code'. nov 06 10:06:50 vw-desk2 systemd[1]: cups.service: start request repeated quickly. nov 06 10:06:50 vw-desk2 systemd[1]: failed start cups scheduler. nov 06 10:06:52 vw-desk2 systemd[1]: cups.service: start request repeated quickly. nov 06 10:06:52 vw-desk2 systemd[1]: failed start cups scheduler. vince@vw-desk2:~$  vince@vw-desk2:~$ systemctl start cups vince@vw-desk2:~$  vince@vw-desk2:~$ systemctl status cups   cups.service - cups scheduler    loaded: loaded (/lib/systemd/system/cups.service; enabled; vendor preset: enabled)    active: failed (result: exit-code) since sun 2016-11-06 11:03:42 gmt; 24s ago      docs: man:cupsd(8)   process: 3664 execstart=/usr/sbin/cupsd -l (code=exited, status=1/failure)  main pid: 3664 (code=exited, status=1/failure)  nov 06 11:03:42 vw-desk2 systemd[1]: started cups scheduler. nov 06 11:03:42 vw-desk2 systemd[1]: cups.service: main process exited, code=exited, status=1/failure nov 06 11:03:42 vw-desk2 systemd[1]: cups.service: unit entered failed state. nov 06 11:03:42 vw-desk2 systemd[1]: cups.service: failed result 'exit-code'. 

/var/log/syslog doesn't jumps out @ me:

nov  6 10:11:54 vw-desk2 anacron[786]: job `cron.daily' terminated nov  6 10:11:54 vw-desk2 anacron[786]: normal exit (1 job run) nov  6 10:17:01 vw-desk2 cron[3371]: (root) cmd (   cd / && run-parts --report /etc/cron.hourly) nov  6 10:19:11 vw-desk2 aptdaemon: info: quitting due inactivity nov  6 10:19:11 vw-desk2 aptdaemon: info: quitting requested nov  6 10:19:11 vw-desk2 org.debian.apt[843]: 10:19:11 aptdaemon [info]: quitting due inactivity nov  6 10:19:11 vw-desk2 org.debian.apt[843]: 10:19:11 aptdaemon [info]: quitting requested nov  6 10:21:52 vw-desk2 systemd[1]: starting cleanup of temporary directories... nov  6 10:21:52 vw-desk2 systemd-tmpfiles[3435]: [/usr/lib/tmpfiles.d/var.conf:14] duplicate line path "/var/log", ignoring. nov  6 10:21:52 vw-desk2 systemd[1]: started cleanup of temporary directories. nov  6 10:28:01 vw-desk2 cron[3481]: (root) cmd (   test -x /etc/cron.daily/popularity-contest && /etc/cron.daily/popularity-contest --crond) nov  6 10:30:29 vw-desk2 systemd-timesyncd[409]: timed out waiting reply 91.189.94.4:123 (ntp.ubuntu.com). nov  6 10:30:29 vw-desk2 systemd-timesyncd[409]: synchronized time server 91.189.89.198:123 (ntp.ubuntu.com). nov  6 11:03:37 vw-desk2 gnome-session[2312]: gtk-message: gtkdialog mapped without transient parent. discouraged. nov  6 11:03:42 vw-desk2 systemd[1]: started cups scheduler. nov  6 11:03:42 vw-desk2 systemd[1]: cups.service: main process exited, code=exited, status=1/failure nov  6 11:03:42 vw-desk2 systemd[1]: cups.service: unit entered failed state. nov  6 11:03:42 vw-desk2 systemd[1]: cups.service: failed result 'exit-code'. nov  6 11:03:42 vw-desk2 kernel: [ 3413.846764] audit_printk_skb: 84 callbacks suppressed nov  6 11:03:42 vw-desk2 kernel: [ 3413.846767] audit: type=1400 audit(1478430222.644:39): apparmor="denied" operation="sendmsg" profile="/usr/sbin/cupsd" name="/run/systemd/journal/socket" pid=3664 comm="cupsd" requested_mask="w" denied_mask="w" fsuid=0 ouid=0 

on second thoughts, last line looks must relevant.

how can printing working again?

this happened me too. working consistently rebooted nothing. found couple of apparmor-denied messages in syslog nothing productive.

then noticed /etc/cups/cupsd.conf had gone missing. problem.

you purse-and-install cups-daemon it ship default-level config file can copy over.

sudo cp /usr/share/cups/cupsd.conf.default /etc/cups/cupsd.conf sudo service cups restart