Arduino IDE 2.3.10 gets stuck on the loading screen

gaby_wiii · August 2, 2026, 5:56pm

Hi! This is my first post. I have a problem. I'm trying to use Arduino IDE 2.3.10, but it gets stuck on the loading screen with the animated logo. I've uninstalled and reinstalled it several times. I can use the 1.x versions, but not the 2.x ones. The following code is from the PowerShell window:

PS C:\Program Files\Arduino IDE> & ".\Arduino IDE"
PS C:\Program Files\Arduino IDE>
Arduino IDE 2.3.10
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: "2.3.10" (type of string)
Setting 'theia.frontend.config.cliVersion' application configuration value to: "1.5.1" (type of string)
Setting 'theia.frontend.config.buildDate' application configuration value to: "2026-06-09T16:48:46.639Z" (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}${appName}","files.autoSave":"afterDelay","editor.minimap.enabled":false,"editor.tabSize":2,"editor.scrollBeyondLastLine":false,"editor.quickSuggestions":{"other":false,"comments":false,"strings":false},"editor.maxTokenizationLineLength":500,"editor.bracketPairColorization.enabled":false,"breadcrumbs.enabled":false,"workbench.tree.renderIndentGuides":"none","explorer.compactFolders":false},"appVersion":"2.3.10","cliVersion":"1.5.1","buildDate":"2026-06-09T16:48:46.639Z"}
Starting backend process. PID: 18480
Showing main window early
Using browser-only version of superagent in non-browser environment
Configuration directory URI: 'file:///c%3A/Users/Usuario/.arduinoIDE'
Configuring to accept webviews on '^.+\.webview\..+$' hostname.
2026-08-02T16:43:03.233Z root WARN Backend u.initialize took longer than the expected maximum 50 milliseconds: 59.5 ms [Finished 1.296 s after backend start]
2026-08-02T16:43:03.240Z root WARN Backend Object.initialize took longer than the expected maximum 50 milliseconds: 54.4 ms [Finished 1.296 s after backend start]
2026-08-02T16:43:03.240Z root INFO Backend a.initialize: 2.8 ms [Finished 1.296 s after backend start]
2026-08-02T16:43:03.240Z root INFO Backend a.initialize: 2.3 ms [Finished 1.296 s after backend start]
2026-08-02T16:43:03.240Z root INFO Backend u.initialize: 2.7 ms [Finished 1.297 s after backend start]
2026-08-02T16:43:03.244Z root WARN Backend l.initialize took longer than the expected maximum 50 milliseconds: 56.3 ms [Finished 1.298 s after backend start]
2026-08-02T16:43:03.258Z root INFO configured all backend app contributions
2026-08-02T16:43:03.260Z root INFO Backend l.onStart: 2.2 ms [Finished 1.324 s after backend start]
2026-08-02T16:43:03.261Z root INFO Backend d.onStart: 0.2 ms [Finished 1.324 s after backend start]
2026-08-02T16:43:03.263Z root INFO Backend a.onStart: 1.4 ms [Finished 1.325 s after backend start]
2026-08-02T16:43:03.264Z config INFO >>> Initializing CLI configuration...
2026-08-02T16:43:03.264Z root INFO Backend x.onStart: 1.2 ms [Finished 1.327 s after backend start]
2026-08-02T16:43:03.264Z config INFO Loading CLI configuration from c:\Users\Usuario\.arduinoIDE\arduino-cli.yaml...
2026-08-02T16:43:03.265Z daemon INFO Starting daemon from C:\Program Files\Arduino IDE\resources\app\lib\backend\resources\arduino-cli.exe...
2026-08-02T16:43:03.265Z root INFO Backend w.onStart: 0.9 ms [Finished 1.328 s after backend start]
2026-08-02T16:43:03.265Z discovery-log INFO start
2026-08-02T16:43:03.265Z discovery-log INFO start new deferred
2026-08-02T16:43:03.265Z root INFO Backend v.onStart: 0.9 ms [Finished 1.329 s after backend start]
2026-08-02T16:43:03.265Z root INFO Backend a.onStart: 0.5 ms [Finished 1.330 s after backend start]
2026-08-02T16:43:03.286Z root INFO Theia app listening on http://127.0.0.1:53615.
2026-08-02T16:43:03.287Z root INFO Finished starting backend application: 21.2 ms [Finished 1.352 s after backend start]
2026-08-02T16:43:03.399Z root WARN The local plugin referenced by local-dir:/c%3A/Users/Usuario/.arduinoIDE/plugins does not exist.
2026-08-02T16:43:03.399Z root WARN The local plugin referenced by local-dir:/c%3A/Users/Usuario/.arduinoIDE/deployedPlugins does not exist.
2026-08-02T16:43:03.399Z root WARN The local plugin referenced by local-dir:C:\Users\Usuario\.arduinoIDE\plugins does not exist.
2026-08-02T16:43:03.411Z config INFO Loaded CLI configuration: {"board_manager":{"additional_urls":[]}}
2026-08-02T16:43:03.411Z config INFO Loading fallback CLI configuration to get 'directories.data' and 'directories.user'
2026-08-02T16:43:03.534Z root INFO Resolve plugins list: 258.8 ms [Finished 1.599 s after backend start]
2026-08-02T16:43:04.059Z daemon INFO time="2026-08-02T12:43:03-04:00" level=info msg="arduino-cli version 1.5.1"
time="2026-08-02T12:43:03-04:00" level=info msg="Using config file: c:\\Users\\Usuario\\.arduinoIDE\\arduino-cli.yaml"
time="2026-08-02T12:43:03-04:00" level=info msg="Executing `arduino-cli daemon`"
Daemon is now listening on 127.0.0.1:53619
{"IP":"127.0.0.1","Port":"53619"}
2026-08-02T16:43:04.059Z daemon INFO Daemon is running.
2026-08-02T16:43:04.156Z daemon INFO time="2026-08-02T12:43:04-04:00" level=info msg="Starting download" url="https://downloads.arduino.cc/libraries/library_index.tar.bz2"
2026-08-02T16:43:04.797Z daemon INFO time="2026-08-02T12:43:04-04:00" level=info msg="Loading hardware from: C:\\Users\\Usuario\\AppData\\Local\\Arduino15\\packages"
time="2026-08-02T12:43:04-04:00" level=info msg="Loading libraries index file" index="C:\\Users\\Usuario\\AppData\\Local\\Arduino15\\library_index.json"
time="2026-08-02T12:43:04-04:00" level=info msg="Adding libraries dir" dir="C:\\Users\\Usuario\\AppData\\Local\\Arduino15\\libraries" isSingleLibrary=false location=ide
time="2026-08-02T12:43:04-04:00" level=info msg="Adding libraries dir" dir="C:\\Users\\Usuario\\Documents\\Arduino\\libraries" isSingleLibrary=false location=user
2026-08-02T16:43:04.801Z root ERROR Detected an error response during the gRPC core client initialization: code: 3, message: Error descargando el ├¡ndice 'https://downloads.arduino.cc/libraries/library_index.tar.bz2': Download failed: server returned 403 Forbidden
2026-08-02T16:43:04.801Z root ERROR Detected an error response during the gRPC core client initialization: code: 9, message: Loading index file: loading json index file C:\Users\Usuario\AppData\Local\Arduino15\package_index.json: open C:\Users\Usuario\AppData\Local\Arduino15\package_index.json: El sistema no puede encontrar el archivo especificado.
2026-08-02T16:43:04.803Z 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
2026-08-02T16:43:04.804Z 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
2026-08-02T16:43:04.804Z 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\Usuario\AppData\Local\Arduino15\library_index.json: El sistema no puede encontrar el archivo especificado.
2026-08-02T16:43:05.067Z config INFO Loaded fallback CLI configuration: {"directories":{"user":"C:\\Users\\Usuario\\Documents\\Arduino","data":"C:\\Users\\Usuario\\AppData\\Local\\Arduino15"}}
2026-08-02T16:43:05.067Z config INFO Merged CLI configuration with the fallback: {"directories":{"user":"C:\\Users\\Usuario\\Documents\\Arduino","data":"C:\\Users\\Usuario\\AppData\\Local\\Arduino15"},"board_manager":{"additional_urls":[]}}
2026-08-02T16:43:05.067Z config INFO Loaded the CLI configuration.
2026-08-02T16:43:05.102Z config INFO Mapped the CLI configuration: {"dataDirUri":"file:///c%3A/Users/Usuario/AppData/Local/Arduino15","sketchDirUri":"file:///c%3A/Users/Usuario/Documents/Arduino","additionalUrls":[],"network":"none","locale":"en"}
2026-08-02T16:43:05.102Z config INFO Validating the CLI configuration...
2026-08-02T16:43:05.126Z config INFO The CLI config is valid.
2026-08-02T16:43:05.126Z config INFO <<< Initialized the CLI configuration.
2026-08-02T16:43:05.128Z 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\Usuario\AppData\Local\Arduino15\package_index.json: open C:\Users\Usuario\AppData\Local\Arduino15\package_index.json: El sistema no puede encontrar el archivo especificado.
[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\Usuario\AppData\Local\Arduino15\library_index.json: El sistema no puede encontrar el archivo especificado.

2026-08-02T16:43:05.147Z daemon INFO time="2026-08-02T12:43:05-04:00" level=info msg="Updating index" url="https://downloads.arduino.cc/packages/package_index.tar.bz2"
2026-08-02T16:43:05.150Z daemon INFO time="2026-08-02T12:43:05-04:00" level=info msg="Starting download" url="https://downloads.arduino.cc/packages/package_index.tar.bz2"
2026-08-02T16:43:05.163Z root INFO core-client-provider [platform-index] Descargando el ├¡ndice: package_index.tar.bz2

2026-08-02T16:43:05.169Z daemon INFO time="2026-08-02T12:43:05-04:00" level=info msg="Starting download" url="https://downloads.arduino.cc/libraries/library_index.tar.bz2"
2026-08-02T16:43:05.174Z root INFO core-client-provider [library-index] Descargando el ├¡ndice: library_index.tar.bz2

2026-08-02T16:43:05.447Z root INFO Deploy plugins list: 2173.0 ms [Finished 3.513 s after backend start]
2026-08-02T16:43:05.625Z root ERROR Failed to update platform, library indexes. Error: 13 INTERNAL: Error descargando el ├¡ndice 'https://downloads.arduino.cc/libraries/library_index.tar.bz2': Download failed: server returned 403 Forbidden
    at t.callErrorFromStatus (C:\Program Files\Arduino IDE\resources\app\lib\backend\main.js:2:3120866)
    at Object.onReceiveStatus (C:\Program Files\Arduino IDE\resources\app\lib\backend\main.js:2:6725569)
    at Object.onReceiveStatus (C:\Program Files\Arduino IDE\resources\app\lib\backend\main.js:2:2604071)
    at C:\Program Files\Arduino IDE\resources\app\lib\backend\main.js:2:4353123
    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:2:6725336)
    at s.updateLibrariesIndex (C:\Program Files\Arduino IDE\resources\app\lib\backend\main.js:2:3119959)
    at C:\Program Files\Arduino IDE\resources\app\lib\backend\main.js:2:6330853
    at C:\Program Files\Arduino IDE\resources\app\lib\backend\main.js:2:6331046
    at new Promise (<anonymous>)
    at y.doUpdateIndex (C:\Program Files\Arduino IDE\resources\app\lib\backend\main.js:2:6331025)
    at y.updateLibraryIndex (C:\Program Files\Arduino IDE\resources\app\lib\backend\main.js:2:6330825)
    at y.updateIndex (C:\Program Files\Arduino IDE\resources\app\lib\backend\main.js:2:6330099)
    at y.initInstanceWithFallback (C:\Program Files\Arduino IDE\resources\app\lib\backend\main.js:2:6328331)
    at async y.create (C:\Program Files\Arduino IDE\resources\app\lib\backend\main.js:2:6327943)
2026-08-02T16:43:05.799Z daemon INFO time="2026-08-02T12:43:05-04:00" level=info msg="Starting download" url="https://downloads.arduino.cc/libraries/library_index.tar.bz2"
2026-08-02T16:43:05.851Z root INFO creating connection for 1
2026-08-02T16:43:06.352Z root ERROR Detected an error response during the gRPC core client initialization: code: 3, message: Error descargando el ├¡ndice 'https://downloads.arduino.cc/libraries/library_index.tar.bz2': Download failed: server returned 403 Forbidden
2026-08-02T16:43:06.352Z root ERROR Detected an error response during the gRPC core client initialization: code: 9, message: Loading index file: loading json index file C:\Users\Usuario\AppData\Local\Arduino15\package_index.json: open C:\Users\Usuario\AppData\Local\Arduino15\package_index.json: El sistema no puede encontrar el archivo especificado.
2026-08-02T16:43:06.353Z daemon INFO time="2026-08-02T12:43:06-04:00" level=info msg="Loading hardware from: C:\\Users\\Usuario\\AppData\\Local\\Arduino15\\packages"
2026-08-02T16:43:06.355Z daemon INFO time="2026-08-02T12:43:06-04:00" level=info msg="Loading libraries index file" index="C:\\Users\\Usuario\\AppData\\Local\\Arduino15\\library_index.json"
2026-08-02T16:43:06.355Z daemon INFO time="2026-08-02T12:43:06-04:00" level=info msg="Adding libraries dir" dir="C:\\Users\\Usuario\\AppData\\Local\\Arduino15\\libraries" isSingleLibrary=false location=ide
2026-08-02T16:43:06.356Z 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
2026-08-02T16:43:06.356Z 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
2026-08-02T16:43:06.357Z 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\Usuario\AppData\Local\Arduino15\library_index.json: El sistema no puede encontrar el archivo especificado.
2026-08-02T16:43:06.360Z 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\Usuario\AppData\Local\Arduino15\package_index.json: open C:\Users\Usuario\AppData\Local\Arduino15\package_index.json: El sistema no puede encontrar el archivo especificado.
[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\Usuario\AppData\Local\Arduino15\library_index.json: El sistema no puede encontrar el archivo especificado.

2026-08-02T16:43:06.360Z 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\Usuario\AppData\Local\Arduino15\package_index.json: open C:\Users\Usuario\AppData\Local\Arduino15\package_index.json: El sistema no puede encontrar el archivo especificado.
[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\Usuario\AppData\Local\Arduino15\library_index.json: El sistema no puede encontrar el archivo especificado.

    at C:\Program Files\Arduino IDE\resources\app\lib\backend\main.js:2:6329842
    at y.evaluateErrorStatus (C:\Program Files\Arduino IDE\resources\app\lib\backend\main.js:2:6329858)
    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:2:6329528)
2026-08-02T16:43:06.361Z daemon INFO time="2026-08-02T12:43:06-04:00" level=info msg="Adding libraries dir" dir="C:\\Users\\Usuario\\Documents\\Arduino\\libraries" isSingleLibrary=false location=user
2026-08-02T16:43:08.839Z root WARN Frontend a.configure took longer than the expected maximum 100 milliseconds: 443.4 ms [Finished 5.436 s after frontend start]
2026-08-02T16:43:08.906Z 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'.
2026-08-02T16:43:09.018Z root WARN Frontend keybindings.onStart took longer than the expected maximum 100 milliseconds: 105.8 ms [Finished 5.595 s after frontend start]
2026-08-02T16:43:09.166Z root INFO Start frontend contributions: 1018.9 ms [Finished 5.728 s after frontend start]
2026-08-02T16:43:09.167Z root INFO Changed application state from 'init' to 'started_contributions'.
2026-08-02T16:43:09.200Z root INFO Changed application state from 'started_contributions' to 'attached_shell'.2026-08-02T16:43:09.201Z root INFO >>> Restoring the layout state...
2026-08-02T16:43:09.302Z root INFO [260edc6b-4f9b-4323-8f43-a7ed99c5a40e] Waiting for backend deployment: 157.0 ms [Finished 5.875 s after frontend start]
2026-08-02T16:43:11.024Z root INFO [hosted-plugin: 13504] PLUGIN_HOST(13504) starting instance
[Object: null prototype] {}
2026-08-02T16:43:12.419Z root INFO [260edc6b-4f9b-4323-8f43-a7ed99c5a40e] Sync of 23 plugins: 3142.7 ms [Finished 9.018 s after frontend start]
Closing channel on service path '/services/electron-window'.
Closing channel on service path '/services/ide-updater'.
Stored workspaces roots:
No sketches were scheduled for deletion.

I don’t know if this is relevant or if it helps identify the issue, but I live in Venezuela, and many websites—including the official Arduino site—don’t allow me access unless I use a VPN. Sometimes I can’t access the forum either (though this isn't consistent).

BitSeeker · August 2, 2026, 8:01pm

It does look like your computer is unable to access that URL. I tried it here and it does immediately try to download the file, which of course may be of no comfort to you in Venezuela. Have you tried putting that URL in the browser address bar?

@ptillisch is generally the expert with these kinds of issues and if it is the kind of issue you suspect, then he may be able to suggest a workaround.

gaby_wiii · August 2, 2026, 8:14pm

I can't access it unless I enable the browser's VPN. I'm currently installing a VPN for the computer to see if that solves the problem.

BitSeeker · August 2, 2026, 8:15pm

You might be able to get it to open if your edit the settings.json file in the arduinoIDE directory and add/change the following setting to:

"arduino.checkForUpdates": false

If its being added then make sure its before the final bracket. This will prevent the IDE from checking for updates on launch. Of course that means you won't get notified of any board or library updates. If it works, the VPN may be the better solution.

gaby_wiii · August 2, 2026, 8:33pm

Installing the VPN on the computer was enough. Thank you very much for taking the time to reply; sorry for the trouble. I'm still going to try your recommendation to avoid problems in the future.

BitSeeker · August 2, 2026, 8:45pm

No worries. Glad the VPN solved the problem. This does appear to confirm that this was a problem with the IDE not being able to access the required Internet resource.

sterretje · August 3, 2026, 4:35am

FYI

After a fresh install of IDE 2.x it needs access to the internet to be able to install some additional files (e.g. the AVR board package).
After that, internet access is no longer needed.

berthapresley · August 5, 2026, 12:52pm

Same here, I will check it by installing the VPN and I hope it resolves my issue too.

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