- Download https://www.sunfounder.com/learn/download/UkZJRF9raXRfVjEuMF9mb3JfQXJkdWluby56aXA=/dispa
- Copy RFID kit V1.0 for Arduino\Library\LiquidCrystal_I2C from the downloaded file to C:\Users\USERNAME\Documents\Arduino\libraries.
- Restart the Arduino IDE if it's running.
- Try compiling/uploading the code again.