I've been having this same 0XC9C70000 problem for months now, and no one at HP will even tell us exactly what the error code means or what causes it. I've tried all the suggested fixes, and nothing has worked. On top of that, this printer has always had a ridiculous habit of going thru some sort of stupid "maintenance procedure" about every 2nd or 3rd time I turn it on. What a stupid piece of junk. Mine's about to go into the garbage can, and never again will I buy another HP printer.
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