Arduino IDE won't open

Development Tools IDE 2.x
1

The logo keeps getting smaller and bigger but nothing happens.I’m on win 10. I saw another posts talking about it but didn’t find my problem.Using powershell to open it I get this error (I’ll translate what is in another language):

The following problems were detected during the gRPC client initialization:
[library-index] - code: 9, message: Loading index file: 
reading library_index.json: open C:\Users\arthu\AppData\Local\Arduino15\library_index.json: 
The system can't find the especified file at C:\Program Files\Arduino IDE\resources\app\lib\backend\main.js:2:6283973 at y.evaluateErrorStatus 
(C:\Program Files\Arduino IDE\resources\app\lib\backend\main.js:2:6283989) at 
process.processTicksAndRejections (node:internal/process/task_queues:95:5) at 
async a.<anonymous> (C:\Program Files\Arduino 
IDE\resources\app\lib\backend\main.js:2:6283659)

A clean install didn’t help

2

Hi @deus1abacate. Please provide the full output from the PowerShell terminal. You don't need to translate it.

I'll provide instructions you can follow to do that:

:red_exclamation_mark: This procedure is not intended to solve the problem. The purpose is to gather more information.

  1. Close all Arduino IDE windows if the IDE is already running.
  2. Start Windows "File Explorer".
  3. Open the Arduino IDE installation folder.
    ⓘ The default installation location is at one of the following paths: 
    • C:\Program Files\Arduino IDE

    • C:\Users\<username>\AppData\Local\Programs\Arduino IDE
      (where <username> is your Windows username)
      :red_exclamation_mark: If looking for it with your file manager or command line, note that the AppData folder is hidden by default. On Windows "File Explorer", you can make it visible by opening the "View" menu, then checking the box next to "☐ Hidden items".
  4. In the folder listing of the Arduino IDE installation folder, hold the Shift key while clicking the right hand button on the mouse.
    A context menu will open
  5. Select "Open PowerShell window here" from the menu.
    Windows PowerShell will now open with the current directory set to the Arduino IDE installation folder.
  6. Type the following command in the PowerShell window:
    & ".\Arduino IDE"
  7. Press the Enter key.
    Debug output should now be printed to the PowerShell window as Arduino IDE starts.
  8. Wait until you are sure the IDE startup has gone into the hang state
    (as indicated by no additional output being printed to the terminal).
  9. Switch back to the PowerShell window if the Arduino IDE window took the focus.
  10. Press the Ctrl+Shift+A keyboard shortcut.
    This will select all the text in the PowerShell window.
  11. Press the Ctrl+C keyboard shortcut.
    This will copy the contents of the PowerShell window to the clipboard.
  12. Open a reply here on this forum topic by clicking the "Reply" button.
  13. Click the <CODE/> icon on the post composer toolbar.
    This will add the forum's code block markup (```) to your reply to make sure the error messages are correctly formatted.
    Code block icon on toolbar
    Code block icon on toolbar390×118 4.25 KB
  14. Press the Ctrl+V keyboard shortcut.
    This will paste the output into the code block.
  15. Move the cursor outside of the code block markup before you add any additional text to your reply.
  16. Click the "Reply" button to publish the post.

Please let us know if you have any questions or problems while following those instructions.

3

Hi.
i have same problem.
i install lastest version of Win 10 pro
then i install Arduino IDE 2.3.7
when i run Arduino IDE , white window opened and Arduino Logo get smaller and bigger continous
in power shell i see bellow
Thanks for your help and your time :handshake:

PS C:\Users\mre\AppData\Local\Programs\Arduino IDE> & ".\Arduino IDE"
PS C:\Users\mre\AppData\Local\Programs\Arduino IDE>
Arduino IDE 2.3.7
Checking for frontend application configuration customizations. Module path: C:\Users\mre\AppData\Local\Programs\Arduino IDE\resources\app\lib\backend\electron-main.js, destination 'package.json': C:\Users\mre\AppData\Local\Programs\Arduino IDE\resources\app\package.json
Setting 'theia.frontend.config.appVersion' application configuration value to: "2.3.7" (type of string)
Setting 'theia.frontend.config.cliVersion' application configuration value to: "1.3.1" (type of string)
Setting 'theia.frontend.config.buildDate' application configuration value to: "2025-12-17T16:05:25.389Z" (type of string)
Frontend application configuration after modifications: {"applicationName":"Arduino IDE","defaultTheme":{"light":"arduino-theme","dark":"arduino-theme-dark"},"defaultIconTheme":"none","electron":{"windowOptions":{},"showWindowEarly":true,"splashScreenOptions":{},"uriScheme":"arduino-ide"},"defaultLocale":"","validatePreferencesSchema":false,"reloadOnReconnect":true,"uriScheme":"theia","preferences":{"window.title":"${rootName}${activeEditorShort}${appName}","files.autoSave":"afterDelay","editor.minimap.enabled":false,"editor.tabSize":2,"editor.scrollBeyondLastLine":false,"editor.quickSuggestions":{"other":false,"comments":false,"strings":false},"editor.maxTokenizationLineLength":500,"editor.bracketPairColorization.enabled":false,"breadcrumbs.enabled":false,"workbench.tree.renderIndentGuides":"none","explorer.compactFolders":false},"appVersion":"2.3.7","cliVersion":"1.3.1","buildDate":"2025-12-17T16:05:25.389Z"}
Starting backend process. PID: 3956
Showing main window early
Using browser-only version of superagent in non-browser environment
Configuration directory URI: 'file:///c%3A/Users/mre/.arduinoIDE'
Configuring to accept webviews on '^.+\.webview\..+$' hostname.
2026-01-23T05:11:09.907Z root INFO Backend u.initialize: 37.9 ms [Finished 0.808 s after backend start]
2026-01-23T05:11:09.908Z root INFO Backend Object.initialize: 35.7 ms [Finished 0.808 s after backend start]
2026-01-23T05:11:09.908Z root INFO Backend a.initialize: 2.0 ms [Finished 0.808 s after backend start]
2026-01-23T05:11:09.908Z root INFO Backend a.initialize: 1.6 ms [Finished 0.808 s after backend start]
2026-01-23T05:11:09.908Z root INFO Backend u.initialize: 2.2 ms [Finished 0.809 s after backend start]
2026-01-23T05:11:09.911Z root INFO Backend l.initialize: 37.6 ms [Finished 0.810 s after backend start]
2026-01-23T05:11:09.920Z root INFO configured all backend app contributions
2026-01-23T05:11:09.920Z root INFO Backend l.onStart: 1.9 ms [Finished 0.824 s after backend start]
2026-01-23T05:11:09.921Z root INFO Backend d.onStart: 0.2 ms [Finished 0.824 s after backend start]
2026-01-23T05:11:09.922Z root INFO Backend a.onStart: 0.5 ms [Finished 0.824 s after backend start]
2026-01-23T05:11:09.922Z config INFO >>> Initializing CLI configuration...
2026-01-23T05:11:09.922Z root INFO Backend x.onStart: 0.6 ms [Finished 0.825 s after backend start]
2026-01-23T05:11:09.923Z config INFO Loading CLI configuration from c:\Users\mre\.arduinoIDE\arduino-cli.yaml...
2026-01-23T05:11:09.923Z daemon INFO Starting daemon from C:\Users\mre\AppData\Local\Programs\Arduino IDE\resources\app\lib\backend\resources\arduino-cli.exe...
2026-01-23T05:11:09.923Z root INFO Backend w.onStart: 0.5 ms [Finished 0.826 s after backend start]
2026-01-23T05:11:09.923Z discovery-log INFO start
2026-01-23T05:11:09.923Z discovery-log INFO start new deferred
2026-01-23T05:11:09.923Z root INFO Backend v.onStart: 0.3 ms [Finished 0.827 s after backend start]
2026-01-23T05:11:09.923Z root INFO Backend a.onStart: 0.1 ms [Finished 0.827 s after backend start]
2026-01-23T05:11:09.929Z root INFO Theia app listening on http://127.0.0.1:52092.
2026-01-23T05:11:09.929Z root INFO Finished starting backend application: 5.9 ms [Finished 0.833 s after backend start]
2026-01-23T05:11:09.943Z root WARN The local plugin referenced by local-dir:/c%3A/Users/mre/.arduinoIDE/plugins does not exist.
2026-01-23T05:11:09.943Z root WARN The local plugin referenced by local-dir:/c%3A/Users/mre/.arduinoIDE/deployedPlugins does not exist.
2026-01-23T05:11:09.943Z root WARN The local plugin referenced by local-dir:C:\Users\mre\.arduinoIDE\plugins does not exist.
2026-01-23T05:11:09.961Z config INFO Loaded CLI configuration: {"board_manager":{"additional_urls":[]}}
2026-01-23T05:11:09.961Z config INFO Loading fallback CLI configuration to get 'directories.data' and 'directories.user'
2026-01-23T05:11:10.028Z root INFO Resolve plugins list: 103.1 ms [Finished 0.931 s after backend start]
2026-01-23T05:11:10.055Z daemon INFO time="2026-01-22T21:11:10-08:00" level=info msg="arduino-cli version 1.3.1"
time="2026-01-22T21:11:10-08:00" level=info msg="Using config file: c:\\Users\\mre\\.arduinoIDE\\arduino-cli.yaml"
time="2026-01-22T21:11:10-08:00" level=info msg="Executing `arduino-cli daemon`"
Daemon is now listening on 127.0.0.1:52093
{"IP":"127.0.0.1","Port":"52093"}
2026-01-23T05:11:10.055Z daemon INFO Daemon is running.
2026-01-23T05:11:10.066Z config INFO Loaded fallback CLI configuration: {"directories":{"user":"C:\\Users\\mre\\Documents\\Arduino","data":"C:\\Users\\mre\\AppData\\Local\\Arduino15"}}
2026-01-23T05:11:10.066Z config INFO Merged CLI configuration with the fallback: {"directories":{"user":"C:\\Users\\mre\\Documents\\Arduino","data":"C:\\Users\\mre\\AppData\\Local\\Arduino15"},"board_manager":{"additional_urls":[]}}
2026-01-23T05:11:10.066Z config INFO Loaded the CLI configuration.
2026-01-23T05:11:10.075Z config INFO Mapped the CLI configuration: {"dataDirUri":"file:///c%3A/Users/mre/AppData/Local/Arduino15","sketchDirUri":"file:///c%3A/Users/mre/Documents/Arduino","additionalUrls":[],"network":"none","locale":"en"}
2026-01-23T05:11:10.076Z config INFO Validating the CLI configuration...
2026-01-23T05:11:10.085Z config INFO The CLI config is valid.
2026-01-23T05:11:10.085Z config INFO <<< Initialized the CLI configuration.
2026-01-23T05:11:10.087Z daemon INFO time="2026-01-22T21:11:10-08:00" level=info msg="Starting download" url="https://downloads.arduino.cc/libraries/library_index.tar.bz2"
2026-01-23T05:11:10.813Z root INFO Deploy plugins list: 888.7 ms [Finished 1.717 s after backend start]
2026-01-23T05:11:11.361Z root INFO creating connection for 1
2026-01-23T05:11:12.576Z root WARN Frontend a.configure took longer than the expected maximum 100 milliseconds: 152.8 ms [Finished 2.636 s after frontend start]
2026-01-23T05:11:12.625Z root WARN A command editor.action.toggleStickyScroll is already registered.
Opening channel for service path '/services/electron-window'.
Opening channel for service path '/services/ide-updater'.
2026-01-23T05:11:12.784Z root INFO Start frontend contributions: 437.8 ms [Finished 2.822 s after frontend start]
2026-01-23T05:11:12.784Z root INFO Changed application state from 'init' to 'started_contributions'.
2026-01-23T05:11:12.798Z root INFO Changed application state from 'started_contributions' to 'attached_shell'.
2026-01-23T05:11:12.798Z root INFO >>> Restoring the layout state...
2026-01-23T05:11:12.848Z root INFO [8eb9b481-54bb-4b8f-a717-d26e323cc78a] Waiting for backend deployment: 89.1 ms [Finished 2.903 s after frontend start]
2026-01-23T05:11:13.594Z root INFO [hosted-plugin: 10288] PLUGIN_HOST(10288) starting instance
[Object: null prototype] {}
2026-01-23T05:11:14.521Z root INFO [8eb9b481-54bb-4b8f-a717-d26e323cc78a] Sync of 23 plugins: 1678.0 ms [Finished 4.581 s after frontend start]