Sainsmart LCD 2004 - LiquidCrytal_I2C library issue unable to compile
I just bought 3 of these that work well with this library
 LiquidCrystal_I2C2004V1.zip
(License: CC BY-NC 2012 http://www.wikispaces.com/user/view/TerryKing).

When installing this library in Arduino IDE (version 1.6 or later), use menu item Sketch | Include&nbsp;Library | Add&nbsp;.ZIP&nbsp;Library..., navigate to the folder where LiquidCrystal_I2C2004V1.zip was downloaded, and then open the zip file.

Use the I2C address in the example "HelloWorld" supplied with LiquidCrystal_I2C2004V1:

//YWROBOT
//Compatible with the Arduino IDE 1.0
//Library version:1.1
#include &lt;Wire.h&gt; 
#include &lt;LiquidCrystal_I2C.h&gt;

LiquidCrystal_I2C lcd(0x27,20,4);  // set the LCD address to 0x27 for a 16 chars and 2 line display

void setup()
{
  lcd.init();                      // initialize the lcd 
  lcd.init();
  // Print a message to the LCD.
  lcd.backlight();
  lcd.setCursor(3,0);
  lcd.print("Hello, world!");
  lcd.setCursor(2,1);
  lcd.print("Ywrobot Arduino!");
   lcd.setCursor(0,2);
  lcd.print("Arduino LCM IIC 2004");
   lcd.setCursor(2,3);
  lcd.print("Power By Ec-yuan!");
}


void loop()
{
}


Do not change the other library directory name; this one is compatible with the existing library. Just add it as a contributed library.