The I2C backpack for LCD displays is a very convenient way to add a character display to your project.
The LCD display with the 1602 controller is probably the most popular display, supported by the I2C backpack.
A common problem is that there are several different libraries for that display, written and supported by different authors, but all named "LiquidCrystal_I2C". If you get and install the wrong one, the sample sketches in our courses will not work as expected.
Here's what to do if you do run into problems in order to recover from an incorrect library:
Step 1. DELETE any library with the name LiquidCrystal_I2C from your Arduino IDE.
Step 2. Install the library that I use in my demonstrations at https://github.com/marcoschwartz/LiquidCrystal_I2C
Step 3. Restart the Arduino IDE
Step 3. Try again with the same sketch.
This will resolve the problem of using an incorrect library. If the issues you experienced that lead you to read this article are due to an incorrect library, that those problems should also be resolved as a result of installing the correct library.