>So the solution is to download and install the MP980 driver that was last released for OS X 10.9. Note that Gatekeeper may stop this from being installed due to the digital signature being for an older OS X. The workaround is to right-click on the printer driver installer and select Open from the pop-up menu that appears. You will now have the option to install the driver.<
Thank you!!
I just found this after having the same issue. Downloading that driver worked perfectly.
Since it was designed to install in OS 10.9.x, We had no problem installing it in Yosemite 10.10.4. There are no unsigned .kxt issues and the installer behaves.
Canon should understand that printers bundled with iMacs 6 years ago might still be going strong – as is the 6 year old iMac. (the MP980 was a clickable option with a $100 rebate when purchased together through the Apple Store) in 2009.
Just updated that iMac with an SSD and new NV RAM (PRAM) battery and expect a few years more life. Glad to report that we don't have to replace a perfectly good printer before its time.