| Issue | Cause | Solution | | :--- | :--- | :--- | | | Corrupted IDE install or selecting the wrong board. | Reinstall Arduino IDE. Ensure the correct board (e.g., Arduino Uno) is selected under Tools -> Board . | | Code hangs at Wire.begin() | Hardware short circuit or missing pull-up resistors. | Ensure SDA and SCL lines have pull-up resistors (usually 4.7kΩ). Check for short circuits. | | Scanner finds no devices | Wrong pins or connection issues. | Double-check wiring. On Uno, SDA is A4 and SCL is A5. | | Linker Error | Using C++ features incompatible with the specific core. | Ensure you are not including <iostream> in a standard Arduino sketch, as this causes memory issues with Wire . |