Comment 311 for bug 554172

Unbelievable: After many years with Ubuntu-12.04 to 16.04, followed by Linux Mint up to 19.3 (Ubuntu 18.04), I switched to a fresh new install of Lubuntu-19.04 a week ago... and have this strange printer disappear problem for the first time ever!

Today is May 18th, 2019 - that is over threet years(!!!) after the last entry in this list.

How can that be? What's wrong?

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My printing system for the last 12-15 years based on cups with the following setup:

* 1 network laser printer
* 3 "symbolic" printers which are a copy of the former, to set defaults for particular uses: "monoprinter" (grayscale), "colorprinter" (full color) and "labelprinter" (use of manual feed)

# lpstat -s
device for Brother_MFC_9142CDN: ipp://BRN30055C78CF3B.local:631/ipp/print
device for colorprinter: ipp://BRN30055C78CF3B.local:631/ipp/print
device for labelprinter: ipp://BRN30055C78CF3B.local:631/ipp/print
device for monoprinter: ipp://BRN30055C78CF3B.local:631/ipp/print

# ls -l ppd/
total 96
-rw-rw-r-- 1 root lp 8619 May 12 18:07 Brother_MFC_9142CDN.ppd
-rw-rw-r-- 1 root lp 8619 May 12 18:07 Brother_MFC_9142CDN.ppd.O
-rw-r----- 1 root lp 8617 May 17 21:00 colorprinter.ppd
-rw-r----- 1 root lp 8635 May 17 20:56 colorprinter.ppd.O
-rw-r----- 1 root lp 8622 May 17 21:05 labelprinter.ppd
-rw-r----- 1 root lp 8622 May 17 21:01 labelprinter.ppd.O
-rw-r----- 1 root lp 8620 May 17 20:59 monoprinter.ppd
-rw-r----- 1 root lp 8635 May 17 20:58 monoprinter.ppd.O

Besides the different settings in /etc/cups/printers.conf, the DeviceURI is the same for all four while the UUID differs:

<Printer Brother_MFC_9142CDN>
UUID urn:uuid:f81a64b6-71d2-3878-71cf-1b1fd6b4dba3
DeviceURI ipp://BRN30055C78CF3B.local:631/ipp/print
</Printer>
<Printer colorprinter>
UUID urn:uuid:63efeecc-be6e-3065-6c0c-9a73bdd0dd62
DeviceURI ipp://BRN30055C78CF3B.local:631/ipp/print
</Printer>
<Printer labelprinter>
UUID urn:uuid:756313d5-4548-327f-666b-9f2edf2c8942
DeviceURI ipp://BRN30055C78CF3B.local:631/ipp/print
</Printer>
<DefaultPrinter monoprinter>
UUID urn:uuid:c4abcfb1-c1f2-34fd-4e8f-514209e3e5e9
DeviceURI ipp://BRN30055C78CF3B.local:631/ipp/print
</DefaultPrinter>

Any help / hint / solution is highly appreciated - TIA.