I only use the genuine refils in my Canon i3400 printer, but since renewing one of the inks, each time I go to print, I get a message that the printer does not recognise the ink. On opening the top of the printer, one of the lights is not on. (always the same one). Removing and putting the cartridge back in, the light comes on and all goes fine until the next time I go to print and the same thing happens all over again. Always the same colour. This is a recently replaced one. Has anyone ever had a 'dodgy' cartridge and if so, I will take it back to the supplyer. (NOT bought cheap off the web!), but I don't want to bother the shop if there MAY be another known reason. Thanks.Keytapper,I'm an Epson user myself. However a phenomenon of Epson (fairly recent) may also be a factor with Canon.When you say genuine Canon REFILLS do you mean commercially sold Canon refills sold exclusively for use in Canon printers originating from Canon?The issue with Epson now is that in order to ensure that you "must" buy their refills they now include a small CHIP that "talks" to the printer. If it is not the correct chip or is another product other than the one produced by the manufacturer of the printer--then it will not be recognized and will CAUSE the printer not to work at all.Is it possible that the last "refill" cartride was an after market one or that it was purchased from a service that refills cartridges?If it is either a Canon original cartride that was NEVER refilled by anyone or is an original that WAS refilled by a refilling service i would take it back in both cases.Good luck,truenorth