Arduino IDE 1.8.2 won't start

My IDE 1.8.12 just suddenly stopped working on Win10 after working for weeks. At the splash screen it would just disappear. Running the arduino_debug showed some java error but google didnt help.

Tried the fix from boweeble above (adding Java variable to Windows Enviornment variables) and it fixed it. Thanks bowebble !

My IDE is crashing due to Java NullPointerExceptions trying to access the boards manager packages. Once the exceptions are thrown and I close the IDE, I can't restart until I delete "%appdata%/roaming/package_index.json".

Doing a fresh install of the latest IDE version does NOT fix the problem (at least at the time of posting).

I am new to arduino, so we just wait until its fixed?

I got the Java NullPointerException error from arduino_debug.exe and the solution was to delete the Arduino15 directory in AppData/Local. But that Arduino15 directory keeps regenerating itself, even when you uninstall Arduino and do a fresh install, so you have to keep deleting it!

Same problem, impossible to use the IDE. Arduino15 folder comes back when setting the sketchbook folder...

Edit: I set the file preferences.txt in read only and it works until it create .json, .sig Edit 2: I unchecked "check updates at start" and these files 4 won't be created.

camilov87: Going to C:\Users\user\AppData\Local\ and deleting the Arduino15 folder solved the problem for me.

I was using dual monitor

My savior.

My arduino IDE started to crash unexpectedly right before the screen was supposed to display after working well for about a month. I deleted the Arduino15 folder and it worked fine after that..

Deleted C:\Users\NAME???\AppData\Local\Arduino15 and reran. Arduino opened and Arduino15 reinstalled. NOTE: Had to un-hide AppData.

This issue was really driving me nuts. This is how I solved it on Windows: 1 - Uninstall Arduino. 2 - Open the folder explorer on windows, go to C: and search for "Arduino". 3 - Wait until all folders appear on the search result. You will see one: "user/AppData/Arudino. (Also one reading "..Arduino15".) No need to delete the Arduino Libraries folder. 4 - Delete that folder. 5 - Install new IDE 1.8.2

When looking manually for the folder, I couldn't find it, but it did come out using search.

Hope this helps!!

It will start for 2 second. Then nothing happing after. Ran debug.

Loading configuration…
Initializing packages…
java.lang.NullPointerException
at cc.arduino.contributions.packages.ContributionsIndexer.parseIndex(ContributionsIndexer.java:134)
at processing.app.BaseNoGui.initPackages(BaseNoGui.java:483)
at processing.app.Base.(Base.java:273)
at processing.app.Base.main(Base.java:150)

Need help.

Same problem. Splash screen for two seconds, which then disappears. Deleting the Arduino15 folder makes it all work again, but that's not an option. Because it also the deletes additional boards settings. No more ESP8266 or ESP32.

There have been many 'forced logins' over the past weeks, and now this. Is this a case of 'fix it until it's broken'? Leo..

I posted a solution to this problem for Windows, based on deleting the Appdata/Arduino folder, but now I believe I found the real issue:

Window has always had a problem with the limitation of depth of directory ramification + filename. So when Arduino IDE tries to open a .ino file which exceeds this (meaning, too many folders within folder to get to the file + long filename) it fails, so does not open.

To make it worse, Arduino IDE always opens with the last code you saved, even if you're just clicking the .exe file. So if your last .ino file saved exceeded the limit, Arduino IDE wont open.

So I solved this by renaming this last file which caused the problem to "a.ino" and it's folder to "a" which made it possible to open the Arduino IDE again.

Uninstalling Arduino, deleting the Appdata/Arduino folder and reinstalling will make Arduino IDE forget which was the last file so it will open, on a blank code, but as soon as you try to open another file which exceed windows depth of directory + filename, Arduino will fail again. So avoid the too-many-folders-with-long-names issue.

Hope this helps!!

acdombro76:
It will start for 2 second. Then nothing happing after. Ran debug.

Loading configuration…
Initializing packages…
java.lang.NullPointerException
at cc.arduino.contributions.packages.ContributionsIndexer.parseIndex(ContributionsIndexer.java:134)
at processing.app.BaseNoGui.initPackages(BaseNoGui.java:483)
at processing.app.Base.(Base.java:273)
at processing.app.Base.main(Base.java:150)

Need help.

same results

I emailed Arduino support about this, we'll see what happens. Problem has been all over the forum today.

Same thing all of a sudden wouldn't start.

As for Camilov87, Going to C:\Users\user\AppData\Local\ and deleting the Arduino15 folder solved the problem for me. Tx to Camilov87

Using Windows 10. I have Deleted Arduino15 folder, uninstalled Arduino completely from all locations, and installed a fresh new install of Arduino 1.8.12, and this did not fix the IDE startup issue for me.

How ever the Arduino IDE will start and run if I delete the file "package_index.json" in the Arduino15 folder, but after restarting the IDE it will not run again, the issue is related to "package_index.json".

I hope a fix for this comes out soon.

Deleting the package_index.json file or Arduino15 folder does fix it. I believe the issue comes back if you try to install the latest version of a board using a board manager. It does not do this successfully. However, I was able to install an older version of the board I wanted using the board manager and it seems to work.

The problem has since been fixed.

Must delete these two broken files.

remove file C:\Users\YourUsername\AppData\Local\Arduino15\package_index.json remove folder C:\Users\YourUsername\AppData\Local\Arduino15\cache

Arduino will re-generate them with the fixed ones. Leo..

More information of the issue is found here with a fix.

Arduino IDE fails to start (with solution)

https://github.com/arduino/Arduino/issues/10345