Arduino IDE 2.3.6 stuck on start up

Development Tools IDE 2.x
1

I have installed the Arduino 2.3.6 for Windows 11 however it is stuck on the start up screen. What can I do to get it operating?

2 
PS C:\Program Files\Arduino IDE> & ".\Arduino IDE"
PS C:\Program Files\Arduino IDE>
Arduino IDE 2.3.6
Checking for frontend application configuration customizations. Module path: C:\Program Files\Arduino IDE\resources\app\lib\backend\electron-main.js, destination 'package.json': C:\Program Files\Arduino IDE\resources\app\package.json
Setting 'theia.frontend.config.appVersion' application configuration value to: "2.3.6" (type of string)
Setting 'theia.frontend.config.cliVersion' application configuration value to: "1.2.0" (type of string)
Setting 'theia.frontend.config.buildDate' application configuration value to: "2025-04-09T11:26:55.498Z" (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}${appName}","files.autoSave":"afterDelay","editor.minimap.enabled":false,"editor.tabSize":2,"editor.scrollBeyondLastLine":false,"editor.quickSuggestions":{"other":false,"comments":false,"strings":false},"editor.maxTokenizationLineLength":500,"editor.bracketPairColorization.enabled":false,"breadcrumbs.enabled":false,"workbench.tree.renderIndentGuides":"none","explorer.compactFolders":false},"appVersion":"2.3.6","cliVersion":"1.2.0","buildDate":"2025-04-09T11:26:55.498Z"}
Starting backend process. PID: 11580
Showing main window early
Using browser-only version of superagent in non-browser environment
Configuration directory URI: 'file:///c%3A/Users/josiah.a.garcia/.arduinoIDE'
Configuring to accept webviews on '^.+\.webview\..+$' hostname.
2025-09-01T19:01:23.341Z root INFO Backend u.initialize: 36.5 ms [Finished 0.986 s after backend start]
2025-09-01T19:01:23.341Z root INFO Backend Object.initialize: 34.6 ms [Finished 0.986 s after backend start]
2025-09-01T19:01:23.341Z root INFO Backend a.initialize: 1.6 ms [Finished 0.986 s after backend start]
2025-09-01T19:01:23.341Z root INFO Backend a.initialize: 1.3 ms [Finished 0.986 s after backend start]
2025-09-01T19:01:23.341Z root INFO Backend u.initialize: 1.7 ms [Finished 0.987 s after backend start]
2025-09-01T19:01:23.344Z root INFO Backend l.initialize: 36.2 ms [Finished 0.988 s after backend start]
2025-09-01T19:01:23.352Z root INFO configured all backend app contributions
2025-09-01T19:01:23.353Z root INFO Backend l.onStart: 1.5 ms [Finished 1.000 s after backend start]
2025-09-01T19:01:23.353Z root INFO Backend d.onStart: 0.1 ms [Finished 1.000 s after backend start]
2025-09-01T19:01:23.354Z root INFO Backend a.onStart: 0.4 ms [Finished 1.000 s after backend start]
2025-09-01T19:01:23.354Z config INFO >>> Initializing CLI configuration...
2025-09-01T19:01:23.354Z root INFO Backend x.onStart: 0.4 ms [Finished 1.001 s after backend start]
2025-09-01T19:01:23.354Z config INFO Loading CLI configuration from c:\Users\josiah.a.garcia\.arduinoIDE\arduino-cli.yaml...
2025-09-01T19:01:23.354Z daemon INFO Starting daemon from C:\Program Files\Arduino IDE\resources\app\lib\backend\resources\arduino-cli.exe...
2025-09-01T19:01:23.354Z root INFO Backend w.onStart: 0.4 ms [Finished 1.001 s after backend start]
2025-09-01T19:01:23.354Z discovery-log INFO start
2025-09-01T19:01:23.354Z discovery-log INFO start new deferred
2025-09-01T19:01:23.354Z root INFO Backend v.onStart: 0.2 ms [Finished 1.002 s after backend start]
2025-09-01T19:01:23.355Z root INFO Backend a.onStart: 0.1 ms [Finished 1.002 s after backend start]
2025-09-01T19:01:23.359Z root INFO Theia app listening on http://127.0.0.1:56370.
2025-09-01T19:01:23.359Z root INFO Finished starting backend application: 4.7 ms [Finished 1.007 s after backend start]
2025-09-01T19:01:23.369Z root WARN The local plugin referenced by local-dir:/c%3A/Users/josiah.a.garcia/.arduinoIDE/plugins does not exist.
2025-09-01T19:01:23.369Z root WARN The local plugin referenced by local-dir:/c%3A/Users/josiah.a.garcia/.arduinoIDE/deployedPlugins does not exist.
2025-09-01T19:01:23.369Z root WARN The local plugin referenced by local-dir:C:\Users\josiah.a.garcia\.arduinoIDE\plugins does not exist.
2025-09-01T19:01:23.386Z config INFO Loaded CLI configuration: {"board_manager":{"additional_urls":[]}}
2025-09-01T19:01:23.386Z config INFO Loading fallback CLI configuration to get 'directories.data' and 'directories.user'
2025-09-01T19:01:23.435Z root INFO Resolve plugins list: 78.8 ms [Finished 1.082 s after backend start]
2025-09-01T19:01:23.451Z daemon INFO time="2025-09-01T15:01:23-04:00" level=info msg="arduino-cli version 1.2.0"
2025-09-01T19:01:23.451Z daemon INFO time="2025-09-01T15:01:23-04:00" level=info msg="Using config file: c:\\Users\\josiah.a.garcia\\.arduinoIDE\\arduino-cli.yaml"
time="2025-09-01T15:01:23-04:00" level=info msg="Executing `arduino-cli daemon`"
2025-09-01T19:01:23.466Z daemon INFO Daemon is now listening on 127.0.0.1:56371
{"IP":"127.0.0.1","Port":"56371"}
2025-09-01T19:01:23.466Z daemon INFO Daemon is running.
2025-09-01T19:01:23.474Z config INFO Loaded fallback CLI configuration: {"directories":{"user":"C:\\Users\\josiah.a.garcia\\Documents\\Arduino","data":"C:\\Users\\josiah.a.garcia\\AppData\\Local\\Arduino15"}}
2025-09-01T19:01:23.474Z config INFO Merged CLI configuration with the fallback: {"directories":{"user":"C:\\Users\\josiah.a.garcia\\Documents\\Arduino","data":"C:\\Users\\josiah.a.garcia\\AppData\\Local\\Arduino15"},"board_manager":{"additional_urls":[]}}
2025-09-01T19:01:23.474Z config INFO Loaded the CLI configuration.
2025-09-01T19:01:23.483Z config INFO Mapped the CLI configuration: {"dataDirUri":"file:///c%3A/Users/josiah.a.garcia/AppData/Local/Arduino15","sketchDirUri":"file:///c%3A/Users/josiah.a.garcia/Documents/Arduino","additionalUrls":[],"network":"none","locale":"en"}
2025-09-01T19:01:23.483Z config INFO Validating the CLI configuration...
2025-09-01T19:01:23.485Z config INFO The CLI config is valid.
2025-09-01T19:01:23.485Z config INFO <<< Initialized the CLI configuration.
2025-09-01T19:01:23.494Z daemon INFO time="2025-09-01T15:01:23-04:00" level=info msg="Starting download" url="https://downloads.arduino.cc/libraries/library_index.tar.bz2"
2025-09-01T19:01:23.568Z root ERROR Detected an error response during the gRPC core client initialization: code: 3, message: Error downloading index 'https://downloads.arduino.cc/libraries/library_index.tar.bz2': Get "https://downloads.arduino.cc/libraries/library_index.tar.bz2": dial tcp [2606:4700::6812:b15]:443: connectex: An attempt was made to access a socket in a way forbidden by its access permissions.
2025-09-01T19:01:23.568Z root ERROR Detected an error response during the gRPC core client initialization: code: 9, message: Loading index file: loading json index file C:\Users\josiah.a.garcia\AppData\Local\Arduino15\package_index.json: open C:\Users\josiah.a.garcia\AppData\Local\Arduino15\package_index.json: The system cannot find the file specified.
2025-09-01T19:01:23.568Z root ERROR Detected an error response during the gRPC core client initialization: code: 9, message: Error loading hardware platform: discovery builtin:serial-discovery not found
2025-09-01T19:01:23.568Z root ERROR Detected an error response during the gRPC core client initialization: code: 9, message: Error loading hardware platform: discovery builtin:mdns-discovery not found
2025-09-01T19:01:23.569Z root ERROR Detected an error response during the gRPC core client initialization: code: 9, message: Loading index file: reading library_index.json: open C:\Users\josiah.a.garcia\AppData\Local\Arduino15\library_index.json: The system cannot find the file specified.
2025-09-01T19:01:23.574Z root ERROR The primary packages indexes are missing. Running indexes update before initializing the core gRPC client The index of the cores and libraries must be updated before initializing the core gRPC client.
The following problems were detected during the gRPC client initialization:
[platform-index] - code: 9, message: Loading index file: loading json index file C:\Users\josiah.a.garcia\AppData\Local\Arduino15\package_index.json: open C:\Users\josiah.a.garcia\AppData\Local\Arduino15\package_index.json: The system cannot find the file specified.
[platform-index] - code: 9, message: Error loading hardware platform: discovery builtin:serial-discovery not found
[platform-index] - code: 9, message: Error loading hardware platform: discovery builtin:mdns-discovery not found
[library-index] - code: 9, message: Loading index file: reading library_index.json: open C:\Users\josiah.a.garcia\AppData\Local\Arduino15\library_index.json: The system cannot find the file specified.

2025-09-01T19:01:23.574Z daemon INFO time="2025-09-01T15:01:23-04:00" level=info msg="Loading hardware from: C:\\Users\\josiah.a.garcia\\AppData\\Local\\Arduino15\\packages"
time="2025-09-01T15:01:23-04:00" level=info msg="Loading libraries index file" index="C:\\Users\\josiah.a.garcia\\AppData\\Local\\Arduino15\\library_index.json"
time="2025-09-01T15:01:23-04:00" level=info msg="Adding libraries dir" dir="C:\\Users\\josiah.a.garcia\\AppData\\Local\\Arduino15\\libraries" isSingleLibrary=false location=ide
time="2025-09-01T15:01:23-04:00" level=info msg="Adding libraries dir" dir="C:\\Users\\josiah.a.garcia\\Documents\\Arduino\\libraries" isSingleLibrary=false location=user
2025-09-01T19:01:23.574Z daemon INFO time="2025-09-01T15:01:23-04:00" level=info msg="Updating index" url="https://downloads.arduino.cc/packages/package_index.tar.bz2"
2025-09-01T19:01:23.581Z daemon INFO time="2025-09-01T15:01:23-04:00" level=info msg="Starting download" url="https://downloads.arduino.cc/libraries/library_index.tar.bz2"
time="2025-09-01T15:01:23-04:00" level=info msg="Starting download" url="https://downloads.arduino.cc/packages/package_index.tar.bz2"
2025-09-01T19:01:23.582Z root INFO core-client-provider [library-index] Downloading index: library_index.tar.bz2

2025-09-01T19:01:23.583Z root INFO core-client-provider [platform-index] Downloading index: package_index.tar.bz2

2025-09-01T19:01:23.586Z root ERROR Failed to update platform, library indexes. Error: 13 INTERNAL: Error downloading index 'https://downloads.arduino.cc/libraries/library_index.tar.bz2': Get "https://downloads.arduino.cc/libraries/library_index.tar.bz2": dial tcp [2606:4700::6812:b15]:443: connectex: An attempt was made to access a socket in a way forbidden by its access permissions.
    at t.callErrorFromStatus (C:\Program Files\Arduino IDE\resources\app\lib\backend\main.js:2:3089094)
    at Object.onReceiveStatus (C:\Program Files\Arduino IDE\resources\app\lib\backend\main.js:2:6681994)
    at Object.onReceiveStatus (C:\Program Files\Arduino IDE\resources\app\lib\backend\main.js:2:2571739)
    at C:\Program Files\Arduino IDE\resources\app\lib\backend\main.js:2:4307911
    at process.processTicksAndRejections (node:internal/process/task_queues:77:11)
for call at
    at s.makeServerStreamRequest (C:\Program Files\Arduino IDE\resources\app\lib\backend\main.js:2:6681761)
    at s.updateLibrariesIndex (C:\Program Files\Arduino IDE\resources\app\lib\backend\main.js:2:3088187)
    at C:\Program Files\Arduino IDE\resources\app\lib\backend\main.js:2:6284984
    at C:\Program Files\Arduino IDE\resources\app\lib\backend\main.js:2:6285177
    at new Promise (<anonymous>)
    at y.doUpdateIndex (C:\Program Files\Arduino IDE\resources\app\lib\backend\main.js:2:6285156)
    at y.updateLibraryIndex (C:\Program Files\Arduino IDE\resources\app\lib\backend\main.js:2:6284956)
    at y.updateIndex (C:\Program Files\Arduino IDE\resources\app\lib\backend\main.js:2:6284230)
    at y.initInstanceWithFallback (C:\Program Files\Arduino IDE\resources\app\lib\backend\main.js:2:6282462)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
2025-09-01T19:01:23.594Z root ERROR Detected an error response during the gRPC core client initialization: code: 3, message: Error downloading index 'https://downloads.arduino.cc/libraries/library_index.tar.bz2': Get "https://downloads.arduino.cc/libraries/library_index.tar.bz2": dial tcp [2606:4700::6812:b15]:443: connectex: An attempt was made to access a socket in a way forbidden by its access permissions.
2025-09-01T19:01:23.594Z root ERROR Detected an error response during the gRPC core client initialization: code: 9, message: Loading index file: loading json index file C:\Users\josiah.a.garcia\AppData\Local\Arduino15\package_index.json: open C:\Users\josiah.a.garcia\AppData\Local\Arduino15\package_index.json: The system cannot find the file specified.
2025-09-01T19:01:23.594Z root ERROR Detected an error response during the gRPC core client initialization: code: 9, message: Error loading hardware platform: discovery builtin:serial-discovery not found
2025-09-01T19:01:23.594Z root ERROR Detected an error response during the gRPC core client initialization: code: 9, message: Error loading hardware platform: discovery builtin:mdns-discovery not found
2025-09-01T19:01:23.594Z root ERROR Detected an error response during the gRPC core client initialization: code: 9, message: Loading index file: reading library_index.json: open C:\Users\josiah.a.garcia\AppData\Local\Arduino15\library_index.json: The system cannot find the file specified.
2025-09-01T19:01:23.596Z root ERROR Uncaught Exception:  Error: The index of the cores and libraries must be updated before initializing the core gRPC client.
The following problems were detected during the gRPC client initialization:
[platform-index] - code: 9, message: Loading index file: loading json index file C:\Users\josiah.a.garcia\AppData\Local\Arduino15\package_index.json: open C:\Users\josiah.a.garcia\AppData\Local\Arduino15\package_index.json: The system cannot find the file specified.
[platform-index] - code: 9, message: Error loading hardware platform: discovery builtin:serial-discovery not found
[platform-index] - code: 9, message: Error loading hardware platform: discovery builtin:mdns-discovery not found
[library-index] - code: 9, message: Loading index file: reading library_index.json: open C:\Users\josiah.a.garcia\AppData\Local\Arduino15\library_index.json: The system cannot find the file specified.

2025-09-01T19:01:23.596Z root ERROR Error: The index of the cores and libraries must be updated before initializing the core gRPC client.
The following problems were detected during the gRPC client initialization:
[platform-index] - code: 9, message: Loading index file: loading json index file C:\Users\josiah.a.garcia\AppData\Local\Arduino15\package_index.json: open C:\Users\josiah.a.garcia\AppData\Local\Arduino15\package_index.json: The system cannot find the file specified.
[platform-index] - code: 9, message: Error loading hardware platform: discovery builtin:serial-discovery not found
[platform-index] - code: 9, message: Error loading hardware platform: discovery builtin:mdns-discovery not found
[library-index] - code: 9, message: Loading index file: reading library_index.json: open C:\Users\josiah.a.garcia\AppData\Local\Arduino15\library_index.json: The system cannot find the file specified.

    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)
2025-09-01T19:01:23.596Z daemon INFO time="2025-09-01T15:01:23-04:00" level=info msg="Starting download" url="https://downloads.arduino.cc/libraries/library_index.tar.bz2"
time="2025-09-01T15:01:23-04:00" level=info msg="Loading hardware from: C:\\Users\\josiah.a.garcia\\AppData\\Local\\Arduino15\\packages"
time="2025-09-01T15:01:23-04:00" level=info msg="Loading libraries index file" index="C:\\Users\\josiah.a.garcia\\AppData\\Local\\Arduino15\\library_index.json"
time="2025-09-01T15:01:23-04:00" level=info msg="Adding libraries dir" dir="C:\\Users\\josiah.a.garcia\\AppData\\Local\\Arduino15\\libraries" isSingleLibrary=false location=ide
time="2025-09-01T15:01:23-04:00" level=info msg="Adding libraries dir" dir="C:\\Users\\josiah.a.garcia\\Documents\\Arduino\\libraries" isSingleLibrary=false location=user
2025-09-01T19:01:23.919Z root INFO Deploy plugins list: 563.5 ms [Finished 1.567 s after backend start]
2025-09-01T19:01:24.696Z root INFO creating connection for 1
2025-09-01T19:01:25.858Z root WARN Frontend a.configure took longer than the expected maximum 100 milliseconds: 133.1 ms [Finished 2.487 s after frontend start]
2025-09-01T19:01:25.891Z 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'.
2025-09-01T19:01:26.017Z root INFO Start frontend contributions: 369.2 ms [Finished 2.633 s after frontend start]
2025-09-01T19:01:26.017Z root INFO Changed application state from 'init' to 'started_contributions'.
2025-09-01T19:01:26.026Z root INFO Changed application state from 'started_contributions' to 'attached_shell'.
2025-09-01T19:01:26.026Z root INFO >>> Restoring the layout state...
2025-09-01T19:01:26.062Z root INFO [56f18340-a5c5-4c3a-958e-d0fc7d31a34c] Waiting for backend deployment: 59.5 ms [Finished 2.688 s after frontend start]
2025-09-01T19:01:26.777Z root INFO [hosted-plugin: 12688] PLUGIN_HOST(12688) starting instance
[Object: null prototype] {}
2025-09-01T19:01:27.835Z root INFO [56f18340-a5c5-4c3a-958e-d0fc7d31a34c] Sync of 23 plugins: 1777.0 ms [Finished 4.465 s after frontend start]
3

Anything special about your network setup? Firewall settings, vpn, company computer/network?

4

yes, there is a firewall and is a company computer. I downloaded the library_index json file and the library_index.json.sig file. Would placing them into the Arduino file help or does it need more than that?

5

There is more. Once you have those files the IDE needs to have access to the internet to download the 64board packages. Without that the IDE can't compile your sketches.

I suggest that you contact the IT department.

Alternatively, find another Windows computer with the same architecture (32bit / 64bit), install the IDE there, download all needed board packages an next copy the installed board packages over to your PC.
Same approach for libraries or you can download them (from e.g. github) and manually install them.

6

Did you get it to work. I'm having a similar problem. I'm running Windows 11, and the IDE app gets stuck when I launch it. I tried to run as an admin, and I got the same results.

7

Hi @ionphoton. I'm going to ask you to provide some additional information that might help us to identify the problem.

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

Please do this:

  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.

It is not necessary to run Arduino IDE as admin, and I recommend against doing this.