HPLIP 3.20.6 Installation Problem

[and003]

I have just completed a troubleshooting exercise of comparing my old /etc/cups (working on Ubuntu 16.04) configuration with my new /etc/cups (not working on Ubuntu 18.04) configuration.

Started from the point where printer was not detected in localhost:631.

I have Krusader installed as a file manager and with two panes it is easier to compare old directory with new. I observed differences in file sizes and some files were missing in my new configuration.

I also noticed there is /etc/cupshelpers folder alongside /etc/cups.

To cut a long story short I changed the folder names in my new directory to /etc/_cups and /etc/_cupshelper just to back them up.

Next I copied /etc/cups and /etc/cupshelpers from old (16.04) to new (18.04).
For good measure I restarted Ubuntu.

And on viewing localhost:631 I was back in business. Printer showed in browser.

Did you have 16.04 and 18.04 on your computer at the same time? I only installed 20.04 on mine and no other Ubuntu version. Indeed, I reinstalled it today to start with a clean slate with regards to a printer installation using HPLIP 3.20.3, adding Cinnamon and LXDE as I went along.

Which brings me to a clue that might interest you. When I plugged my printer into an USB port after the reinstallation, the 'system-config-printer' program detected it as a network printer, signalling that it is connected to localhost, but when I went to localhost:631 and pressed the "Find New Printers" button, the aforementioned 'No Printers Found' error message appeared. Also, when I clicked on the "Add Printer" button, this came up:

http://localhost:631 is requesting your username and password. The site says: "CUPS"

Perhaps using my printer as a Network printer might be an avenue I can pursue? I could devise my own username and password in the process. I was using the Cinnamon desktop environment at the time I plugged the printer into the USB port if it matters. Also, when I click on the "Manage Printers" button, my printer does show up.

[dragonfly41]

Did you have 16.04 and 18.04 on your computer at the same time?

Sorry, I should have explained that I have an old Ubuntu 16.04 installed alongside Windows 10 in /dev/sda
and in /dev/sdb I have Ubuntu 18.04 installed on an SSD in a docking bay. This way I can refer back to old installations.

I have solved my problem of missing printer and I posted the above workflow not as a question but perhaps to help you in your troubleshooting.

...

However, although my printer is recognised I have just tried printing and I get this message ..

"The PPD version (5.2.11) is not compatible with Gutenprint 5.2.13. Please run `/usr/sbin/cups-genppdupdate' as administrator."

Updated /etc/cups/ppd/HP-LaserJet-2100M.ppd using gutenprint.5.2://hp-lj_2100m/expert
Updated 1 PPD file. Restart cupsd for the changes to take effect.

That works and I printed my job.

[and003]

I've discovered something about my XSane installation that might be connected. When I tried using it without HPLIP, I received this error message:

Failed to open device 'hpaio:/usb/Smart_Tank_Plus_650_series?serial=CN9B8240ZR': Error during device I/O.

Perhaps the answer lies in this particular issue?

[dragonfly41]

I'm sorry I can't throw some more ideas into the pot.

[and003]

I'm sorry I can't throw some more ideas into the pot.

That's okay. I'm certain if I can figure out how to change the driver through the HPLIP interface, the problem should clear up. It will mean contacting the people at HPLIP for assistance, though. In the meantime, I can use other programs for scanning and printing.

[and003]

I wouldn't call it solved, but designating it as such is the only way to close this thread.

[carlo-negri-it]

this is not fair because other users hope a solution has been found, they waste time reading all the posts to find that the problem has not been solved

[coffeecat]

this is not fair because other users hope a solution has been found, they waste time reading all the posts to find that the problem has not been solved

I agree. I have removed the solved prefix.

I wouldn't call it solved, but designating it as such is the only way to close this thread.

@and003, please do not do that. It is most discourteous to those searching the internet for solutions to problems. If you want a thread closed, simply click on the "report post" button in your thread opening post to request closure and a member of forum staff will do that for you. I have now closed this thread.