Addendum: In prefs.js, the line: 'user_pref("print.print_printer", "Microsoft Office Document Image Writer")' has "Microsoft Office Document Image Writer" (which is the problem)

I cannot recall what to put on that line for the printer??

It is a Canon (Canon_MP240_series) but I don't know what to put in place of the "Microsoft Office Document Image Writer" In other words how much of the following line do I use? print.printer_Canon_MP240_series_Printer.print

I fixed the problem (at least temporarily)

The line in Firefox's "preference file" "(prefs.js) print.print_printer ----- Name of Printer" Where (Name = print.print_printer, and Value = Name of Printer) had the Value: "Microsoft Office Document Image Writer". (Which was incorrect).

With Firefox closed I replaced the "Microsoft Office Document Image Writer" value with: "Canon MP240 series Printer"and rebooted.

If this applies to anybody, I copied the exact name of my printer (for the value correction) from the printer folder in control panel.

Yesterday I suddenly developed a similar problem. If I opened FILE>PRINT it only offered "save to Microsoft XPS Document Writer" and if I clicked "save" I just got an error popup. When I opened "Print" on the Navigation Toolbar the Printer Name was shown as the XPS Document Writer. However the dropdown arrow produced a list including hp 5500 series which is my printer and when I changed the name all was back to normal. I have no idea how the name got changed to the XPS Document writer. No-one else uses the computer and I never use the Navigation Toolbar print instruction; I always use File>Print. Could it happen as part of a Firefox update?