When I try to set a printer as the default printer on the HP Device Manager,
the Device Manager crashes with the following error:

TypeError: argument 1 must be str or None, not bytes

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/share/hplip/ui5/devmgr5.py", line 2046, in
SetDefaultButton_clicked
    result, result_str = cups.cups_operation(cups.setDefaultPrinter, GUI_MODE,
'qt4', self, self.cur_printer.encode('utf8'))
  File "/usr/share/hplip/prnt/cups.py", line 857, in cups_operation
    result, status_str = operation_func(*cups_op_args)
  File "/usr/share/hplip/prnt/cups.py", line 680, in setDefaultPrinter
    return cupsext.setDefaultPrinter(printer_name)
SystemError: <built-in function setDefaultPrinter> returned a result with an
error set
Abortado

This bug was filed for a very old version of hplip and probably has been fixed in a later upload.  So I am manually closing this bug now.

In case this bug is still present in the latest version of hplip, please reopen the bug.

Unfortunately HP is no longer willing to maintain this software properly and does not even provide a public bug tracker. Meanwhile the Ubuntu Launchpad tracker is ignored as well.
Therefore it is very unlikely that HP becomes aware of this bug and will fix it.

So if you reopen this bug and really want to have this fixed, please also provide a patch.

    Thorsten