I bought a black XL and a colored XL and installed them in my HP ENVY 7640. The printer immediately recognized the black XL cartridge as a repackaged HP cartridge (which it is) but did not recognize the color cartridge. I took out the color cartridge and put it back in 3 times with no success and then I took a damp cloth and wiped the chipset where it made contact with the printer during installation and after that it worked fine. You just have to wipe the contact. Some people might think this should lower my rating, but such a low price for these cartridges makes up for the need to rely on simple life skills like contact point cleaning.