Hope this helps someone else having the same problem. I have an HP 2610 All In One that started giving me "check color cartridge" errors. I tried resetting the printer and seemed to work initially but then it returned a day or so later. Took the cartridge out, cleaned, reinstalled still same error. I read somewhere that the black cartridge could be the problem so I took it out and cleaned it, reinstalled, same problem. Now this is where it gets interesting. I have a supplemental color cartridge (has 4 different cartridge numbers on it, 99/ 138/ 348/ 858) that replaces the black cartridge. Took the black cartridge out and put this one in, message popped up "used color cartridge installed", I clicked OK. Then it said "used tri-color cartridge installed", I clicked OK. It printed a calibration page, no error messages. I then put the black cartridge back in and got "used black cartridge installed". I hit OK, it printed another calibration page and the printer works fine now.