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MF743C says toner cartridge is not inserted correctly


It states specifically the Y toner. I have removed it, replaced it and still get the same msg. There is nothing to really do but drop the cartridge in the slot. So what to do now? 

I originally had the M cartridge spewing ink on paper so i removed the M and Y cart and cleaned up the excess M ink and replaced the carts, Now get the msg that the Y is not inserted correctly.

Help please. My wife is ready to throw it out the window but she is in the basement so wont hurt it.


Product Expert
Product Expert


If the issue began after reseating a leaking toner cartridge, it looks like the contacts for the toner or printer are dirty. In this situation, you can try removing all of the toner cartridges and inspecting the inside of the printer for any loose toner powder that can be wiped up with a damp cloth. Once the printer has been cleaned, you can try reloading the toner to see if that resoles the issue.

If that does not resolve the problem, you can try another toner cartridge to see if it is detected. If that does not work, it looks like the printer needs service. You can contact support at 1-800-652-2666 or you can log into your MyCanon account to check your service options.


same problem here with magenta and yellow, the printer was working fine and all of a sudden prompted that the cartridges are not installed correctly. we have checked all terminals replaced the cartridges with no luck the same problem. I've had this printer for 3 months and am almost done with it I've been burned by HP and cannon now with printers that last less than a couple months

Hello Sonofbum,

If you have already tried reseating the toner and inspecting the inside for any loose toner powder and checked the contacts, it looks like the printer needs service. If you have had the printer for three months, it will be under warranty and you can contact our support team over the phone at 1-800-652-2666. Our agents would be happy to assist with any hardware issues and can provide service options.