When you have to use the Arduino IDE on a public or university computer on which you are not allowed to install anything, you may not be allowed to install any board packages or libraries. Making the Arduino IDE portable solves this problem.
Like most (Windows) applications the Arduino IDE puts its intermediate files and working folders in fixed places on the computer’s hard drive. For most users who always work on their own computer, this will not be a real problem. However, when you have to use a public or university computer on which you cannot install anything, this can pose a problem as it is not possible to install any board packages or libraries. The solution to this is to make the Arduino IDE portable. A portable installation keeps everything in the Arduino IDE installation folder.
Just create a folder named 'portable'
Making the IDE portable is surprisingly easy as all you have to do is add a folder named ‘portable’ to the IDE installation folder, next to the Arduino executable. The next time you launch the IDE it will automatically detect it and use it as its sketchbook location; it will put the board packages and libraries that you install in this folder and it will use it to store intermediate files. Everything will be neatly together in one single folder that you can copy to a thumb drive and use it when- and wherever you may need it.
Future proof your Arduino projects
The portable IDE is also a great way for separating different Arduino installations on a single computer. Since many developers keep updating libraries and board packages all the time, it is easy to break old projects. By installing a fresh portable IDE for every new project that might benefit from it (maybe not for every Blinky) it is easy to protect them against the future.
Archive your Arduino projects
Projects are also easy to archive this way, especially when you use a thumb drive for each project or setup. For instance, create a thumb drive for an IDE with only ESP32-related things on it, and another for quick Arduino Uno experiments.
Create multiple identical environments
The portable folder is portable itself and can be copied to other IDE installations. This allows for quickly setting up identical environments on multiple computers, a feature that teachers and administrators will certainly appreciate.
Except for macOS...
Portable Arduino has issues on macOS due to the operating system’s way of handling user permissions.