Awesometoner Canon X25 Compatible Toner Replacement one year guarantee Not Recognizing: Verify you have the correct cartridge for your specific printer model. Make sure that the cartridge is fully inserted into the printer and is installed correctly. Theres no smart chip on this cartridge. Instead, Canon recommends replacing the toner when the prints are light and rocking the cartridge has no effect. NOTE: The procedure will similar on other Canon printers that use the X25. For exact instructions on a particular Canon printer refer to the Users Guide which is available on Canons website. Print Quality Issues:There is a pull tape seal on the side of the cartridge which must be removed prior to installation. It is important that this pull tape is fully removed. If the cartridge is printing blank pages or printed one page and now prints blank pages then the pull tape seal probably hasnt been removed or has broken off inside the cartridge while being removed. Rock the cartridge 5 or 6 times to distribute the toner evenly inside the cartridge. Not Fitting: Verify you have the correct cartridge for your specific printer model. Check to make sure the pull tape seal has been removed from the side of the cartridge. Check inside the printer for any debris which may be impeding the cartridge from going in. Check the toner cartridge for any physical damage.