IDE hangs on loading

Development Tools IDE 2.x
1

Just downloaded the Arduino IDE to my work computer (running Windows 11 Enterprise), and although everything with installation seemed to work fine, it won't load when I try to launch the app. Just hangs on the splash screen indefinitely. I tried looking at the firewall settings, seeing that many others who get "Error: 14" have had issues related to that, but nothing in them stuck out at me as being related, and because this is a work computer, I don't want to go messing around with network security to try and figure out if that's the problem here.

Anyways, here's what I get when I launch from Powershell with & ".\Arduino IDE"

PS C:\Users\jamiwils\AppData\Local\Programs\Arduino IDE> & ".\Arduino IDE"
PS C:\Users\jamiwils\AppData\Local\Programs\Arduino IDE>
Arduino IDE 2.3.6
Checking for frontend application configuration customizations. Module path: C:\Users\jamiwils\AppData\Local\Programs\Arduino IDE\resources\app\lib\backend\electron-main.js, destination 'package.json': C:\Users\jamiwils\AppData\Local\Programs\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}${appName}","files.autoSave":"afterDelay","editor.minimap.enabled":false,"editor.tabSize":2,"editor.scrollBeyondLastLine":false,"editor.quickSuggestions":{"other":false,"comments":false,"strings":false},"editor.maxTokenizationLineLength":500,"editor.bracketPairColorization.enabled":false,"breadcrumbs.enabled":false,"workbench.tree.renderIndentGuides":"none","explorer.compactFolders":false},"appVersion":"2.3.6","cliVersion":"1.2.0","buildDate":"2025-04-09T11:26:55.498Z"}
Starting backend process. PID: 13980
Showing main window early
Using browser-only version of superagent in non-browser environment
Configuration directory URI: 'file:///c%3A/Users/jamiwils/.arduinoIDE'
Configuring to accept webviews on '^.+\.webview\..+$' hostname.
2025-11-17T16:52:45.903Z root INFO Backend u.initialize: 15.4 ms [Finished 0.329 s after backend start]
2025-11-17T16:52:45.905Z root INFO Backend Object.initialize: 14.6 ms [Finished 0.329 s after backend start]
2025-11-17T16:52:45.905Z root INFO Backend a.initialize: 1.5 ms [Finished 0.329 s after backend start]
2025-11-17T16:52:45.905Z root INFO Backend a.initialize: 1.4 ms [Finished 0.329 s after backend start]
2025-11-17T16:52:45.905Z root INFO Backend u.initialize: 1.6 ms [Finished 0.329 s after backend start]
2025-11-17T16:52:45.906Z root INFO Backend l.initialize: 15.3 ms [Finished 0.330 s after backend start]
2025-11-17T16:52:45.910Z root INFO configured all backend app contributions
2025-11-17T16:52:45.910Z root INFO Backend l.onStart: 0.7 ms [Finished 0.336 s after backend start]
2025-11-17T16:52:45.910Z root INFO Backend d.onStart: 0.1 ms [Finished 0.337 s after backend start]
2025-11-17T16:52:45.911Z root INFO Backend a.onStart: 0.2 ms [Finished 0.337 s after backend start]
2025-11-17T16:52:45.911Z config INFO >>> Initializing CLI configuration...
2025-11-17T16:52:45.911Z root INFO Backend x.onStart: 0.2 ms [Finished 0.337 s after backend start]
2025-11-17T16:52:45.911Z config INFO Loading CLI configuration from c:\Users\jamiwils\.arduinoIDE\arduino-cli.yaml...
2025-11-17T16:52:45.911Z daemon INFO Starting daemon from C:\Users\jamiwils\AppData\Local\Programs\Arduino IDE\resources\app\lib\backend\resources\arduino-cli.exe...
2025-11-17T16:52:45.911Z root INFO Backend w.onStart: 0.2 ms [Finished 0.337 s after backend start]
2025-11-17T16:52:45.911Z discovery-log INFO start
2025-11-17T16:52:45.911Z discovery-log INFO start new deferred
2025-11-17T16:52:45.911Z root INFO Backend v.onStart: 0.1 ms [Finished 0.337 s after backend start]
2025-11-17T16:52:45.911Z root INFO Backend a.onStart: 0.0 ms [Finished 0.338 s after backend start]
2025-11-17T16:52:45.924Z root WARN The local plugin referenced by local-dir:/c%3A/Users/jamiwils/.arduinoIDE/plugins does not exist.
2025-11-17T16:52:45.924Z root WARN The local plugin referenced by local-dir:/c%3A/Users/jamiwils/.arduinoIDE/deployedPlugins does not exist.
2025-11-17T16:52:45.924Z root WARN The local plugin referenced by local-dir:C:\Users\jamiwils\.arduinoIDE\plugins does not exist.
2025-11-17T16:52:45.926Z root INFO Theia app listening on http://127.0.0.1:54077.
2025-11-17T16:52:45.926Z root INFO Finished starting backend application: 15.2 ms [Finished 0.353 s after backend start]
2025-11-17T16:52:45.944Z config INFO Loaded CLI configuration: {"board_manager":{"additional_urls":[]}}
2025-11-17T16:52:45.944Z config INFO Loading fallback CLI configuration to get 'directories.data' and 'directories.user'
2025-11-17T16:52:45.982Z root INFO Resolve plugins list: 70.5 ms [Finished 0.409 s after backend start]
2025-11-17T16:52:46.025Z daemon INFO time="2025-11-17T10:52:46-06:00" level=info msg="arduino-cli version 1.2.0"
2025-11-17T16:52:46.026Z daemon INFO time="2025-11-17T10:52:46-06:00" level=info msg="Using config file: c:\\Users\\jamiwils\\.arduinoIDE\\arduino-cli.yaml"
2025-11-17T16:52:46.026Z daemon INFO time="2025-11-17T10:52:46-06:00" level=info msg="Executing `arduino-cli daemon`"
2025-11-17T16:52:46.034Z daemon INFO Daemon is now listening on 127.0.0.1:54078
{"IP":"127.0.0.1","Port":"54078"}
2025-11-17T16:52:46.034Z daemon INFO Daemon is running.
2025-11-17T16:52:46.038Z config INFO Loaded fallback CLI configuration: {"directories":{"user":"C:\\Users\\jamiwils\\Documents\\Arduino","data":"C:\\Users\\jamiwils\\AppData\\Local\\Arduino15"}}
2025-11-17T16:52:46.038Z config INFO Merged CLI configuration with the fallback: {"directories":{"user":"C:\\Users\\jamiwils\\Documents\\Arduino","data":"C:\\Users\\jamiwils\\AppData\\Local\\Arduino15"},"board_manager":{"additional_urls":[]}}
2025-11-17T16:52:46.038Z config INFO Loaded the CLI configuration.
2025-11-17T16:52:46.041Z config INFO Mapped the CLI configuration: {"dataDirUri":"file:///c%3A/Users/jamiwils/AppData/Local/Arduino15","sketchDirUri":"file:///c%3A/Users/jamiwils/Documents/Arduino","additionalUrls":[],"network":"none","locale":"en"}
2025-11-17T16:52:46.041Z config INFO Validating the CLI configuration...
2025-11-17T16:52:46.043Z config INFO The CLI config is valid.
2025-11-17T16:52:46.043Z config INFO <<< Initialized the CLI configuration.
2025-11-17T16:52:46.141Z root ERROR Uncaught Exception:  Error: 14 UNAVAILABLE: No connection established. Last error: read ECONNRESET (2025-11-17T16:52:46.140Z)
2025-11-17T16:52:46.141Z root ERROR Error: 14 UNAVAILABLE: No connection established. Last error: read ECONNRESET (2025-11-17T16:52:46.140Z)
    at t.callErrorFromStatus (C:\Users\jamiwils\AppData\Local\Programs\Arduino IDE\resources\app\lib\backend\main.js:2:3089094)
    at Object.onReceiveStatus (C:\Users\jamiwils\AppData\Local\Programs\Arduino IDE\resources\app\lib\backend\main.js:2:6679669)
    at Object.onReceiveStatus (C:\Users\jamiwils\AppData\Local\Programs\Arduino IDE\resources\app\lib\backend\main.js:2:2572294)
    at Object.onReceiveStatus (C:\Users\jamiwils\AppData\Local\Programs\Arduino IDE\resources\app\lib\backend\main.js:2:2571739)
    at C:\Users\jamiwils\AppData\Local\Programs\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.makeUnaryRequest (C:\Users\jamiwils\AppData\Local\Programs\Arduino IDE\resources\app\lib\backend\main.js:2:6679200)
    at s.create (C:\Users\jamiwils\AppData\Local\Programs\Arduino IDE\resources\app\lib\backend\main.js:2:3088187)
    at instance (C:\Users\jamiwils\AppData\Local\Programs\Arduino IDE\resources\app\lib\backend\main.js:2:6283083)
    at new Promise (<anonymous>)
    at y.createClient (C:\Users\jamiwils\AppData\Local\Programs\Arduino IDE\resources\app\lib\backend\main.js:2:6283060)
    at y.create (C:\Users\jamiwils\AppData\Local\Programs\Arduino IDE\resources\app\lib\backend\main.js:2:6281968)
    at C:\Users\jamiwils\AppData\Local\Programs\Arduino IDE\resources\app\lib\backend\main.js:2:6280864
    at C:\Users\jamiwils\AppData\Local\Programs\Arduino IDE\resources\app\lib\backend\main.js:2:1018551
    at s.invoke (C:\Users\jamiwils\AppData\Local\Programs\Arduino IDE\resources\app\lib\backend\main.js:2:1018641)
    at a.fire (C:\Users\jamiwils\AppData\Local\Programs\Arduino IDE\resources\app\lib\backend\main.js:2:1020444)
2025-11-17T16:52:46.307Z root INFO Deploy plugins list: 395.6 ms [Finished 0.734 s after backend start]
2025-11-17T16:52:46.886Z root INFO creating connection for 1
2025-11-17T16:52:47.326Z 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'.
2025-11-17T16:52:47.382Z root INFO Start frontend contributions: 155.1 ms [Finished 1.440 s after frontend start]
2025-11-17T16:52:47.382Z root INFO Changed application state from 'init' to 'started_contributions'.
2025-11-17T16:52:47.382Z root INFO Changed application state from 'started_contributions' to 'attached_shell'.
2025-11-17T16:52:47.382Z root INFO >>> Restoring the layout state...
2025-11-17T16:52:47.399Z root INFO [e06073eb-42c2-46d6-b013-a6f58d10572b] Waiting for backend deployment: 27.5 ms [Finished 1.465 s after frontend start]
2025-11-17T16:52:47.652Z root INFO [hosted-plugin: 33880] PLUGIN_HOST(33880) starting instance
[Object: null prototype] {}
2025-11-17T16:52:47.977Z root INFO [e06073eb-42c2-46d6-b013-a6f58d10572b] Sync of 23 plugins: 579.7 ms [Finished 2.045 s after frontend start]

By the way, my colleague tried downloading the IDE on his work computer (same OS, same network) to see if he would have the same issue and it all worked perfectly for him.

2

Hi @j-wils. The availability of Arduino's online assets have been intermittently affected by a major global degradation of the Cloudflare content delivery network used by Arduino (and many other websites across the Internet):

On the first run after a fresh installation, Arduino IDE downloads some additional essential components from the Internet and installs them. If it can't install those components then the startup fails. So the computer must be able to access those downloads in order to start up on that first run. For this reason, the CDN problems might be the cause of the hang you experienced.

At least for me, the Cloudflare situation seems to have stabilized now (though Cloudflare indicates the incident is not yet considered to be completely resolved). So please try starting Arduino IDE again now. Hopefully this time everything will work as expected.

Even at the peak of the incident, it was intermittent. So it might have simply been that your colleague was lucky enough to hit a window of availability, while you did not.

3

I had this happen once, too. I made sure all my sketches and libraries were backed up to another folder on my PC, then uninstalled Arduino entirely, restarted PC, reinstalled Arduino and restarted again. Fixed the issue for me. In fact, it preserved the libraries iirc but it's still wise to back up, of course.

4

I did try both uninstalling and restarting the computer, although not in that order. But with a totally fresh download of the IDE, which I've never used on this computer before, I'm pretty sure I don't have any sketches or libraries on the computer yet.

5

It still isn't working, but I guess I'll keep trying throughout the day, and if that's really the problem maybe I'll get lucky. Thanks for the info. I really hope it's something that simple!