frankieteddie wrote:
Is there a known problem with Canon MX430s and OS X, or could it possibly be a virus or other malware problem?
There is no known issue with the MX430 series on OS X 10.11. And I doubt that you would have malware that is stopping you from printing.
For the USB connected MX, the most common cause for no printing is the cable. I suggest you turn off the printer and unplug the USB cable. Then restart your Mac and after you log back in, reconnect the USB cable and turn the printer back on. Then see if you can print again. And ensure you are selecting the printer for the USB connection. If you have a printer in Printers & Scanners for the MX connected via wireless, and you select this printer when you want to print, then it will not work.
As for the wireless connection not working, if you updated to El Capitan from a previous OS and it was printing fine via wireless, then you often just need to remove this printer and add it again. If you have tried this already and it did not work, then reply and I will see if we can get it connected via wireless again.