When a Canon printer reaches its waste ink limit (100%), it locks up and displays an error to prevent ink from overflowing and damaging the device or your workspace. The Service Tool V4720 allows you to set this counter back to zero, effectively reviving a printer that would otherwise be unusable.
Close the software, turn off the printer via the power button, wait 10 seconds, and turn it back on normally. Frequently Asked Questions (FAQ) Why does the Service Tool say "Not Responding"? Canon Service Tool V4720 Free Download
Ensure your printer is connected via USB cable (Wi-Fi usually does not work for service mode). When a Canon printer reaches its waste ink