CUPS not running - [SOLVED]

[Keith]

I am running Ubuntu 16.04 on a Thinkpad T500. 
When attempting to print to my HP 7610 it didn't appear on the printer list so I checked System-Settings/Printers but there was nothing listed and the Add button was greyed out.  Clicking on Help/Troubleshooting produced the message:
CUPS Service Stopped The CUPS print spooler does not appear to be running. To correct this, choose System->Administration->Services from the main menu and look for the 'cups' service. 
However, I see no Administration->Services option.

Browsing the web I found several other queries about this problem and tried a couple of the suggested solutions:
keith@T500:~$ sudo /etc/init.d/cups start
[sudo] password for keith:
keith@T500:~$ sudo service cups restart
Failed to restart cups.service: Unit cups.service is masked.
But all to no effect.
I tried visiting http://localhost:631/printers/ but it wasn't available. 

I have made no changes to the system other than the usual updates, and would be very grateful for suggestions. 

[Mark Greaves (PCNetSpec)]

Try unmasking the service:

Code: [Select]

service unmask cups.service

then start the cups service with

Code: [Select]

service cups start

If that still doesn't work, try

Code: [Select]

sudo apt-get install --reinstall cups cups-browsed cups-client cups-common cups-daemon cups-server-common

then:

Code: [Select]

sudo systemctl daemon-reload

If that still doesn't work, post the output from:

Code: [Select]

service cups status

and:

Code: [Select]

file /lib/systemd/system/cups.service

[Keith]

Thank you, Mark.  Here is the output....

keith@T500:~$ service unmask cups.service
unmask: unrecognized service
keith@T500:~$ service cups start
Job for cups.socket failed. See "systemctl status cups.socket" and "journalctl -xe" for details.
keith@T500:~$
--------------------------------------------------------------------
keith@T500:~$ sudo apt-get install --reinstall cups cups-browsed cups-client cups-common cups-daemon cups-server-common
[sudo] password for keith:
Reading package lists... Done
Building dependency tree       
.
.
.
Setting up cups-client (2.1.3-4ubuntu0.3) ...
Setting up cups (2.1.3-4ubuntu0.3) ...
Updating PPD files for cups ...
keith@T500:~$ sudo systemctl daemon-reload
keith@T500:~$
--------------------------------------------------------------------
Then I tried: 
System-settings/printers:  Tried to print test page but:
Printer state:  “Idle - File "/usr/lib/cups/filter/hpcups" not available: No such file or directory”
----------------------------------------------------------------------

keith@T500:~$ service cups status
? cups.service - CUPS Scheduler
   Loaded: loaded (/lib/systemd/system/cups.service; enabled; vendor preset: enabled)
   Active: active (running) since Wed 2017-09-20 17:25:29 BST; 8min ago
     Docs: man:cupsd(
 Main PID: 8930 (cupsd)
   CGroup: /system.slice/cups.service
           ??8930 /usr/sbin/cupsd -l
           ??9361 /usr/lib/cups/notifier/dbus dbus://

Sep 20 17:25:29 T500 systemd[1]: Started CUPS Scheduler.
Sep 20 17:25:31 T500 systemd[1]: Started CUPS Scheduler.
Sep 20 17:25:31 T500 systemd[1]: Started CUPS Scheduler.
Sep 20 17:25:52 T500 systemd[1]: Started CUPS Scheduler.
keith@T500:~$ file /lib/systemd/system/cups.service
/lib/systemd/system/cups.service: ASCII text
keith@T500:~$
-----------------------------------------------------------------
Is the missing file /usr/lib/cups/filter/hpcups the problem? 

[Mark Greaves (PCNetSpec)]

Try:

Code: [Select]

sudo apt-get install --reinstall printer-driver-hpcups

But really I don't understand why you're not just using hplip-gui to install your HP printer:

Code: [Select]

sudo apt-get install hplip-gui

Then look for the HPLIP Toolbox in your menu.

[Keith]

sudo apt-get install --reinstall printer-driver-hpcups  had no effect but your comment re hplip GUI caused me to check that it was still installed - which of course it wasn't since my catastrophic computer crash a while ago, when I clearly had forgotten to re-install it, although the printer has been working flawlessly up to yesterday.  It's interesting, though, that that last command didn't supply the missing file. 

I've installed HPLIP it now and all is well.  Very many thanks for your advice, Mark.  As usual!
  Keith

[Mark Greaves (PCNetSpec)]

No problem my mate