Error message: Multiple libraries - IRremote

My IR remote no longer works due to an error message of multiple libraries.

What needs to be done to prevent that message being shown again?

Remove the redundant reference to the library which may be obvious from your code which, if you choose to post it, should be between code tags here.

 Created by Peter Clarke

 HC-SR04 Ultrasonic Range Finder.
 Two motors attached to the motor shield.
 speaker/piezo for sound
 IR remote control
 Thumbstick for whiskers
 3 leds for battery status
 13 - Motor B direction
 12 - Motor A direction
 11 - (blocked by shield)
 10 - Infrared remote receiver
 9  - not used (cut brake connect on bottom of the shield to use)
 8  - not used (cut brake connect on bottom of the shield to use)
 7  - Ping trigger
 6  - Motor B pwm
 5  - Motor A pwm
 4  - Ping echo
 3  - (blocked by shield)
 2  - Sound
 1  - not connected (Serial write)
 0  - not connected (Serial read)
 A0 - Battery LED 1 (cut SNS0 on bottom of the shield to use)
 A1 - Battery LED 2 (cut SNS1 on bottom of the shield to use)
 A2 - Battery LED 3
 A3 - unused
 A4 - Thumbstick vertical
 A5 - Thumbstick horizontal
 Arduino Uno has three timers; timer 0, timer 1, timer 2
 Timers can be used without their output going to the pins, the PWM pins.

  timer 0 (controls pin 5, 6)  
  timer 1 (controls pin 10, 9)
  timer 2 (controls pin 3, 11) 
 Timing functions we use:
  timer 0 - Arduino time functions; millis() and motor speed
  timer 1 - Generates the tones for sound.
  timer 2 - Remote control IR
 PWM (timer) pins we use:
  timer 0 pin 5  - Motor A to control speed.
  timer 0 pin 6  - Motor B to control speed.
  timer 1 pin 9  - Can only be used for digitalRead() & digitalWrite()
  timer 1 pin 10 - IR receiver.    Can only be used for digitalRead() & digitalWrite()
  timer 2 pin 3  - Cannot be used as pin (blocked by shield)
  timer 2 pin 11 - Cannot be used as pin (blocked by shield)

// NewTone - For playing sounds using timer 1
#include <NewTone.h>

#include <IRremote.h>

OK. It can also be that you have loaded a library which has a name clash with an existing library.
The error message may help here.
Can you see anything suspicious under sketch → include library → manage library ?
If so, you can remove it by hand. In Windows, it is probably under Documents → Arduino → Libraries or similar.

I may have deleted it from the libraries in my computer but on the Arduino, IRremote only appears once (but with an IRremoteInt too) yet the multiple programmes occurs.

Does error message, which you have not yet shown, resemble the one here in post #0 ?

Does post #11 + in the same thread help ?

It is

It is

. . . and from the error message, which we still have not seen, you have identified the duplicate library and removed it ?

Every Arduino user has two libraries folders, one for common (system) use in the Arduino IDE installation tree, and one for private use in his sketch book folder. According to C standards the following syntax can be used to select the folder to use

#include "privateLib.h" //searches the sketchbook first
#include <systemLib.h> //searches only in system directory

but the Arduino IDE or toolchain seems to behave differently.

When I edited the IRremote library, the IDE created a copy in my private libraries folder. The copy seems to always take precedence, regardless of the #include syntax, see your compiler warning messages.