Here’s a quick guide on getting the drivers to work for the CanoScan 8400F on Windows 11

The CanoScan 8400F Scanner is nearly 20 years old now, it was annouced in late 2004 and if you want to get a brand new scanner of this calibre you’re looking at well over $1200AUD for an Epson Perfection 850. Sadly my CanoScan 8400F is having a whole host of issues now and is on the way out, so I’ll have to replace it soon.  I did find installing the drivers on Windows a bit difficult, so I figured I’d post some quick notes on how to get it working.

You’ll need to download both the CanoScan Toolbox (Version 4.9.3) and the CanoScan 8400F Drivers (ScanGear CS 10.231a) for Windows 10 64bit.  Here’s a link to the Canon page with both.

When you install the drivers, it will extract some files and then disappear – it works, it just doesn’t tell you.  If for some reason it didn’t work, you can use 7zip to extract the installer to get to the .inf files to manually install the scanner drivers through the Device Manager.

Installing the CanoScan Toolbox seems to work as per usual.

Here’s the trick though!  You need to add the Twain driver path to your environment variables.

To do this, you’ll want to go to:  Settings -> System -> About -> Advanced System Settings -> Environment Variables -> Scroll down to “Path” under System Variables and click on Edit -> Click on “New” and enter the text: C:\Windows\twain_32\CNQ8400

Hit okay a few times and reboot your computer.

Now you can open ScanGear and scan away!