javaScript error occurred in the main process

Version 21.2.0

• Target: Windows x64

My Electron app runs fine using electron from the command line, but after I’ve built it from an executable and try to run it I get:

[Window Title]
Error

[Main Instruction]
A JavaScript error occurred in the main process

[Content]
Uncaught Exception:
Error: The specified module could not be found.
\\?\C:\Users\username\AppData\Local\Temp\808c0bf6-a0f1-4211-a312-7c0cce29173a.tmp.node
    at process.func (electron/js2c/asar.js:140:31)
    at process.func [as dlopen] (electron/js2c/asar.js:140:31)
    at Object.Module._extensions..node (internal/modules/cjs/loader.js:922:18)
    at Object.func (electron/js2c/asar.js:140:31)
    at Object.func [as .node] (electron/js2c/asar.js:149:18)
    at Module.load (internal/modules/cjs/loader.js:735:32)
    at Module._load (internal/modules/cjs/loader.js:648:12)
    at Module._load (electron/js2c/asar.js:717:26)
    at Function.Module._load (electron/js2c/asar.js:717:26)
    at Module.require (internal/modules/cjs/loader.js:775:19)

[OK]

I don’t know how to reproduce the error yet. Does anyone know why the app is attempting to load a module from AppData\Local? What module is this? How do I debug this problem?

[aabuhijleh]

Your app is trying to run a .node file from the %temp% directory. The reason behind this issue is that Windows cannot run node|dll|exeutable files from the asar package => so it copies them to %temp% and tries to execute them there.

To fix this, add this to your electron-builder configuration

"asarUnpack": ["**/*.node"]

[ajmetal]

I eventually discovered this issue is caused by a custom native node module I had created. If a native module fails to load for a myriad of reasons it will present with: Error: The specified module could not be found.

In my case there was a missing dependency the native node module required.