At times your Arduino IDE may take long time to load up & freeze when you click on something.Force closing the application pops up an error message “LAUNCH4J”.

Image 12

If you search for the term Launch4j you may land up on JAVA related solution pages.

Launch4j is a cross-platform tool for wrapping Java applications distributed as jars in lightweight Windows native executables . Launch4j wraps jars in Windows native executables and allows to run them like a regular Windows program.

The Arduino IDE itself is written in JAVA. Launch4j is caused by incompatibility of Java Run Time environment library supplied with Arduino package.For smooth performance of IDE your PC should have the latest Java Run Time Environment.

Following are the solutions to the Launch4j problem.

1. As discussed in the previous post you can rename the Arduino folder inside MyDocuments & ReLaunch the IDE.

2. Turn OFF Bluetooth or WIFI on your PC.

3. You can install the latest JAVA environment and then replace the one inside  Arduino package.

Download the latest JRE from the Oracle website & install it.



Navigate to   C:\ProgramFiles\Java  folder & copy the latest JRE folder






Now locate the java folder that is installed with the Arduino package.It is under




Rename or delete the JAVA folder inside Arduino.

Now paste the JRE folder copied from JAVA installation.Rename jre to java.

That’s all.Re Launch the Arduino IDE for a smooth operation.