Troubleshoot Errors

ImportError:No Module named 'cupsext'

Notes: 

   Extension modules are missing from the current Python path "/usr/lib/python<version>/dist-packages".
This happens when HPLIP is installed using one python version and you are running HPLIP using another python version.
For example, HPLIP was installed using python2.x and running the tools using python3.x

Please ensure to run HPLIP tools using the same version of Python which was used for HPLIP installation or re-install HPLIP from https://developers.hp.com/hp-linux-imaging-and-printing/gethplip

Error: Unable to create print queue, please restart cups and try again

Symptoms: 

Receiving Error: Unable to create print queue, please restart cups and try again

Cause: 

Suse 10.1 comes with CUPS 1.1.23 and in some system configurations may cause the above error

I'd like to view the CUPS error log for debugging and troubleshooting purposes

Applies To
Solution: 

Edit the /etc/cups/cupsd.conf file, find the section "loglevel" change "info" to "debug" save and exit then restart cups

# /etc/init.d/cups restart

or for Ubuntu

$ sudo /etc/init.d/cupsys restart

then enter this command to view the log

tail -f /var/log/cups/error_log

With the CUPS LogLevel set to debug, the CUPS error_log will show all programs that are executed during the print job. Generally there are two data paths taken during a print job; 1) HPIJS driver path 2) Postscript driver path. Both data paths will use the "hp" backend.

For the HPIJS path, look for errors near the ghostscript command (gs) command. The gs command will invoke the HPIJS driver.

For the Postscript path, there will be no gs command. Postscript will be passed directly to the "hp" backend and then to the printer.

Python 3 Limitations

Dependent package installation fails on Fedora

"yum" is the default package manager on Fedora distributions, which is not ported to support Python 3 by Fedora. Fedora has alternate plans for the package manager tool as can be seen in the linkhttp://fedoraproject.org/wiki/Changes/ReplaceYumWithDNF

At present, installation of dependencies for HPLIP fails in Python3 environment on Fedora distributions due to the above limitation. Till the time Fedora makes DNF available and HPLIP includes support for DNF, users will have to manually install the required dependencies for HPLIP as suggested below:

Run the below command in Python2 environment.

su -c "yum install cups cups-devel audit gcc-c++ ghostscript openssl-devel libjpeg-devel net-snmp-devel glibc-headers libtool libusb1-devel make python-imaging sane-backends sane-backends-devel sane-frontends xsane dbus-devel polkit polkit-gnome wget avahi-tools python3 python3-devel python3-PyQt4 python3-pyqt4-dbus python3-dbus avahi-tools python3-gobject python3-pip python3-pillow"

Cannot launch hp-toolbox on OpenSuse and Fedora

For all the opensuse versions lesser than 13.2 and Fedora versions less than 21, "hp-toolbox" cannot be launched.

hp-toolbox is dependent on the shared library "qt.so", which is not shipped with the package "dbus-1-python3" for Python versions less than 3.4.  All the functionalities provided by hp-toolbox work fine through the individual tools like hp-setup, hp-levels, etc.

This limitation is being followed up at,

https://bugzilla.novell.com/show_bug.cgi?id=843493

XSane installation failed message on Debian

During dependent package checks on Debian, HPLIP shows xsane installation has failed. This happens due to a tool "/sbin/gnome-menu-blacklist" which is invoked by the package manager tool apt-get is not ported to support Python3 yet.

In most cases, Xsane is installed but a <<< xsane install failure >>> message is displayed due to apt-get returning a non-zero status.

Continue the installation by typing 'n' when HPLIP tools ask to retry xsane installation.

This limitation is being followed up at,

https://tracker.debian.org/news/346436

Fax

HPLIP currently doesn't support Fax Cover Page in Python3 environments. For enabling Fax Cover Page in  HPLIP, check the official documentation of reportlab at:

http://www.reportlab.com/documentation/relnotes/30/