One day, the client woke up and their Cannon CR-L1 check scanner just wasn't working. It did not show up in the check scanner app despite the client deleting and reinstalling the app, the drivers and multiple reboots on their Windows 11 computer.
https://support.usa.canon.com/kb/s/article/Unable-to-scan-on-Windows-11-24H2-imageFORMULA-Check-scanners
Evidently this is a compatibility issue with the latest version of Windows 11 and the Canon Ranger Driver. They have a temporary pre-release driver on that link available for download until they have a more permanent solution.
More Cannon information: https://community.usa.canon.com/t5/Scanners/Ranger-driver-for-imageFORMULA-CR-L1-amp-CR-50-not-working-after/td-p/532938