No, it won't lock your printhead. It locks down the cartridge serial selection. You may use another set of cartridges to "unlock" it. I keep my Set up cartridges given that the "superior established" only for condition like this. In my situation the unit was coming down even so the http://hp-officejet-pro-6968-pri71482.pages10.com/Everything-about-hp-officejet-pro-8500a-printer-error-33035267