Thank you for posting your solution to your problem.
However, the reason for additional entries on this "solved" issue is that for many of us it is not solved and nowhere close to being solved. The reason it is marked 'solved' is that one person managed, on their own, to get the problem fixed FOR THEM. For the rest of us we have have issues that encompass many different issues all revolving around scanning and MFToolbox. For isstance, it took me over four months to uninstall and reinstall Toolbox and that only got me back to my original problem of Toolbox not recognzing my scanner (not on a network). It has been three or more months now since then and no new communications from Canon. Others have similar issues revolving around scanning, scanner recognition, networking, etc.
Clearly Canon has not allocated any resources, to my knowldege, to fix this vexing interaction with Windows 10, and like most tech companies they refuse to communicate with their customers about progress, if any, on issues important to the customer. The clear lesson is that once you buy a Canon product you are on your own. Period.
Call me delusional but I still fantasize that somehow, some day, Canon will have the blinding epiphany that if they want to have return customers they might, actually, just a little, pay some attention to their current one. But, as I said, I'm delusional.