Please perform these steps:
1. Click on the Apple in the upper left corner.
2. Click on System Preferences.
3. Click on Printers & Scanners.
4. Click 1 time on the MX920 on the left side.
5. On the right side, click on the Scan tab on the top right.
6. Click the Open Scanner button.
Are you able to scan?
If not, what error message appears, specifically, what error code appears at the bottom?
Same problem, also on Big Sur, when I perform the above steps I get a popup error:
The application “Canon IJScanner5” can’t be opened.
With the error code "6"
Then the Image Capture window says "Failed to open a connection to the device (-21345)"
Lots of other people are getting this error if you google it. Always on macOS Big Sur.
09/26/2023: New firmware updates are available.
08/18/2023: Canon EOS R5 C training series is released.
07/31/2023: New firmware updates are available.
05/31/2023: New firmware updates are available.
05/18/2023: New firmware updates are available.
03/30/2023: New firmware updates are available.