After no problems at all with my Canon MP 460 I am now getting the message "The following ink cartridges can not be recognised" with arrows pointing to both B and C. If I try to print I get the same message on my monitor screen but am also told "printing can not be executed because the ink cartridges may not be installed properly or may not be compatible with this printer". Both these statements are simply incorrect, they are installed correctly and have already printed for a number of weeks. Any ideas, please?