An error pops up: `A javaScript error occured in the main process`

[hellojinwoo]

Description

• An error message pops up after I execute the jupyterlab on desktop screen

A javaScript error occured in the main process

uncaught Exception:
Error: connect ECONNERFUSED 127.0.0.1:64279
   at TCPConnectWrap.afterConnect [as oncomplete] (node:net:1142:16)

• I have installed Jupyterlab-desktop, and 2 jupyter extensions, which are darcula theme(https://github.com/telamonian/theme-darcula) and github extension(https://github.com/telamonian/theme-darcula)
• Do not know how to reproduce this error because I don't know how come I got to have this error as well.

Expected behavior

• Can execute the jupyterlab-desktop with the error pop-up screen

Context

• Operating System and version: Windows 11
• JupyterLab-Desktop version: v.3.3.2-1
• Installer: .exe

Troubleshoot Output

Paste the output from running `jupyter troubleshoot` from the terminal inside of JupyterLab-Desktop here.
You may want to sanitize the paths in the output.

Browser Output (required for interface issues after loading)

Paste the output from the DevTools JavaScript console here, if applicable.

Logs (required for issues with loading, server and startup)

Paste the logs from the `main.log` file here (optionally also from `renderer.log`).

[hellojinwoo]

• It seems to have a problem with Server Connection Error
• After I had the error pop-up screen javaScript error occured in the main process, my notebook gets disconnected from Python and it sets back to no kernel

[mbektas]

@hellojinwoo thanks for reporting this issue. Other folks had reported this issue but we couldn't find the exact source of the problem. Server seems to sometimes crash on Windows, during launch. so as a remedy we are restarting the server as mentioned here https://github.com/jupyterlab/jupyterlab-desktop/issues/388#issuecomment-1053643642. Restart is limited to up to 3 times.

Are you consistently getting this error message every time you launch JupyterLab Desktop?

[hellojinwoo]

@mbektas Thank you for the feedback. Yes, I have constantly received the error message whenever I execute the jupyterlab. To solve the problem, I have deleted the jupyterlab-desktop as instructed in the installation page. And then I have reinstalled jupyterlab desktop. But the error keeps showing up.

Now it seems like the only solution would be formatting my laptop, which I wouldn't like to do for real.

• Is there any other solution than formatting my laptop?

[mbektas]

@hellojinwoo is this still a problem for you? have you tried the latest version 3.6.1-1?

[litodemesa]

How can I fix this please help

A JavaScript error occurred in the main process

Uncaught Exception: SyntaxError: Unexpected token'

this is what happened when I start up Jupyterlab

[mbektas]

@litodemesa can you provide logs. instructions here.

[Tigger36]

I am experiencing this issue right now. Was a resolution identified?

[mbektas]

@Tigger36 can you try with the latest version and provide logs if issue persists?

[xiaoxiang01a]

I also experienced this issue. But I found nothing from 'C:\Users\XXX\AppData\Roaming\jupyterlab-desktop\logs\main.log'. There were only records of previous successes there.

Finally,I solved this problem by uninstalling the jupyterlab-desktop, deleting the folder 'C:\Users\XXX\AppData\Roaming\jupyterlab-desktop' and reinstalling the latest version v4.0.7-1.

my device is win10.

[mbektas]

@0915xiaoxiang thanks for sharing your solution. @Tigger36 and @litodemesa could you also try the same?