Cannot install Canon Printer MG3100 Driver

If you didn't manually trash the Canon driver files then they are most likely still present so the action of trying to run the driver installer again is unnecessary. To check if the driver is still present, open Finder and select Go > Go to Folder. Then copy the following text and paste that into the Go to Folder field and then press the Go button.

/Library/Printers/PPDs/Contents/Resources

Now look for a file labelled "CanonIJMG3100series.ppd.gz". If you see it then you still have the Canon driver installed and don't need to run the driver installation again.

You mention the Mac no longer detecting the Canon. This is a result of the Bonjour discovery service failing on your Mac - there are others in the same situation. To get past this issue you can create a direct printer to the MG. To do this you will have to determine what IPv4 address the MG is using. As there is no display on this model you may have to connect to your wireless router to check what IPv4 address has been assigned to the MG. Once you have the IPv4 address then you can select to add a printer, but change from the Default view to the IP view. Then enter the IPv4 address of the MG, set the Protocol to Line Printer Daemon, enter LP for the Queue and change the Name to MG3100. Then select the MG3100 series in the Use menu and click Add to complete the creation of this printer. Now you should be able to print again.

This indicates that the LPR service is not enabled in the MG. For many of these new models the LPR service is enabled by default - maybe your MG31xx was released before Canon started enabling it. So, to enable it open your web browser of choice and enter the IPv4 address of the MG31xx as the URL. This will connect to the internal web page of the printer. Click on the Advanced button and then select Other Settings in the left sidebar. Now you should see an entry labelled LPR protocol setting. Assuming this is set to Disable, change its drop menu to Enable and then click the OK button. Now you should be able to create the printer without that "Unable to verify..." message appearing.

So this would suggest that the IPv4 address you have for the MG31xx is not correct and thus this answers why you got the message above when trying to add the printer.

How did you determine what IPv4 address the MG is using? Is it connecting via wifi or Ethernet to your wireless router?

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