I have Arduino IDE, version 1.8.10 (Windows 10 x64, 8GB RAM, i5-7200 @2.5GHz) on a network drive mapped to D:, on a 100Mbit wired network and fast file server.

If I navigate to the network shared folder and launch 'arduino.exe', it takes at least 2 minutes for the IDE to appear.

This seems totally unreasonable considering the entire arduino.exe file is only 395kB. Seems more likely the IDE is waiting for something until a timeout occurs, before finally loading up the IDE.

What can be causing this and how can I diagnose it?

As an aside, it seems the compilation process takes longer than it should too, even for programs that use no external libraries and are very short.

  • dowload sysinternals process monitor and run it ... it will log everything ... see what the Arduino IDE is doing ... docs.microsoft.com/en-us/sysinternals/downloads/…
    – jsotola
    Commented Dec 6, 2019 at 6:15
  • The libraries and applications used and called sum up to considerable sizes. As @jsotola said, use Sysinternal's process monitor or the task manager to watch these sizes. Commented Dec 6, 2019 at 8:15
  • 2
    arduino.exe is only a launcher. it starts the Java Virtual Machine. Arduino IDE is written in Java. antivirus program can slow down the compilation, because of many process and files opened
    – Juraj
    Commented Dec 6, 2019 at 9:42
  • Did you try installing everything on a local drive? (including all libraries) ? Commented Dec 6, 2019 at 9:53
  • 2
    and the Java used is bundle with IDE installation so on the network drive too
    – Juraj
    Commented Dec 6, 2019 at 10:56

1 Answer 1


The simple answer is "libraries".

Every time you start the application, all files inside your library folder are parsed.

And this is not done over your OS, but over the Java-Virtual Machine.

So it is not just slow, it is ultra-slow! Since your antivirus will probably also check each file.

Once, all files was read (maybe 1/2 of the time spent by your Arduino start), all your sketch folders are parsed.

At the end Windows devices and Arduino specific libraries are loaded.

On my Arduino IDE (is installed locally), on each starts, the Arduino IDE checks about 300.000 files. I need up to 20 seconds to load everything, before I can use the IDE.

What can you do?


  • do not waste the library folder with unused libraries
  • NEVER put some documentation or non-Arduino files in your sketch folder, as they are all parsed by the IDE
  • disable the Antivirus for the folders:
    • Arduino
    • libraries
    • sketch


If you open always the same project, you can for example edit the "preferences.txt" file.

If you remove some parameters from the preferences.txt, you will be able to lauch your IDE much faster. I created an application that statrs your Arduino IDE with personalized settings:

This application can remove some preferences like:

  • boardsmanager
  • last.* settings
  • recent sketches

when the Arduino starts, so it will be launched faster. But if you set the preference sketchbook.path, you can start your Arduino IDE 3-4 times faster. Just place the folder with your project libraries and you can start the IDE much faster.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.