Long-story short: Buy a new printer if you have this error.
My mother-in-law has an older color printer that she got with her iMac in 2009.
HP Photosmart C4480 says “incompatible print cartridge” on its screen and will not do anything at all. Nothing will resolve this problem permanently so don’t bother buying new cartridges (waste of $50) nor cleaning the printer contacts.
Here are some steps to force the printer out of that mode.
- Press X power at the same time
- Press BLUE, GREEN, GRAY
- Press BLUE until you see “INFORMATION MENU”
- Press OK
- Press Blue until you see “CHECKSUM FOR RELOCK DATA INPUT” (about 10 times)
- Press X until you exit all menus
- When prompted for aliement cancel it with X. It should bypass the error
This works for our printer for only as long as the printer is On. If you power the printer off you will have to follow the procedure again. At this point that means that this printer is worthless and we will need to buy a new one.