I'm wondering if there is something wrong like a virus, that keeps rejecting my printers. I have a HP 2820 connected by USB and a Canon Irc2620 connected on the network. Each time I install them, after few days even few hours, it doesn' work anymore. So I install them again, sometimes it take hours, then it works again, and it stops again. All other computers in the office are working and printing without any problem, so I wonder if there is something wrong with the MacPro itself. For exemple, tuesday I called Canon support, they helped me fixing the printer connection, then it stopped again yesterday. I don't know why. Nothing was installed between tuesday and saturday, no different application was launched.