I have (apparently) solved the problem. In several printer definitions printers.conf had a long (some 4000 chars?) configuration line (see at the end of this message). There were recurring errors in cups/error_log stating "Unknown configuration directive" which I had not noticed. I removed the (offending?) printer entries by hand and it seemed to work (tested in my home printer). The rest of the printers (even the ones I removed by hand) seem to be available now. I can see them in the printing dialogs and in the system printer configuration. But the entries I removed (or very similar ones) are back in printers.conf, and now I can stop and re what start cupsd.
One of the entries that cups/error_log complained about is:
Info HP Designjet T520 36in \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
I have (apparently) solved the problem. In several printer definitions printers.conf had a long (some 4000 chars?) configuration line (see at the end of this message). There were recurring errors in cups/error_log stating "Unknown configuration directive" which I had not noticed. I removed the (offending?) printer entries by hand and it seemed to work (tested in my home printer). The rest of the printers (even the ones I removed by hand) seem to be available now. I can see them in the printing dialogs and in the system printer configuration. But the entries I removed (or very similar ones) are back in printers.conf, and now I can stop and re what start cupsd.
One of the entries that cups/error_log complained about is:
Info HP Designjet T520 36in \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\ \\\\\\\
Hope this helps!
Cheers.