

More drastic is to completely remove/delete the printer/scanner from your list in System Preferences and then reinstall everything and add the device back to your printer/scanner list.It would best to first uninstall it, but that may not be straightforward. You can try reinstalling the Toolbox program.The files can be restored if they are found to not be related to the problem. You can try moving these files to a safe place, rebooting, and then seeing if the program functions properly. You may get lots of false "hits," but going through them one by one may pay off. You can also use a program like Find Any File to search everywhere on your Mac for "Canon" and "Toolbox" to find all such support files, both in the Preferences as well as Application Support folder (which is also in the Library). I have an entire folder called Canon there and it has various scanner preference files. Look for the preference files in your user Library folder, Preferences, and then look for any support files or folders with the text "canon" in them.You might try the following, one at a time, to see if any resolve the issue: The MF Toolbox should work through 10.14, however, so you should not be seeing this issue.

However some of the utilities stopped working as the MacOS progressed. We have an ancient Canon MG8120 Printer/Scanner and it actually still works even with Macs on Catalina even though the software tools are advertised as good through MacOS 10.6.
