WebDriverError: session not created - Testing Electron app with WebdriverIO and Cucumber #14708

minh-de-rien · 2025-08-15T14:26:48Z

minh-de-rien
Aug 15, 2025

Hi! I'm trying to write E2E tests for my Electron app using WebdriverIO + Cucumber (BBD). I keep encountering the session creation fails with a "user data directory is already in use" error.

Here is my error

DEBUG electron-service: Setting capability at onWorkerStart [
  {
    browserName: 'chrome',
    browserVersion: '134.0.6998.44',
    'wdio:electronServiceOptions': {
      appBinaryPath: 'C:\\Perso\\myapp.exe'
    },
    'goog:chromeOptions': {
      binary: 'C:\\Perso\\myapp.exe',
      windowTypes: [Array],
      args: [Array]
    },
    'wdio:enforceWebDriverClassic': true
  }
]

 "spec" Reporter:
------------------------------------------------------------------
[chrome 134.0.6998.44 (unknown) #0-0] Running: chrome (v134.0.6998.44) on (unknown)
[chrome 134.0.6998.44 (unknown) #0-0]
[chrome 134.0.6998.44 (unknown) #0-0] ✖ Failed to create a session:
[chrome 134.0.6998.44 (unknown) #0-0] WebDriverError: session not created: probably user data directory is already in use, 
please specify a unique value for --user-data-dir argument, or don't use --user-data-dir when running "http://localhost:58128/session" with method "POST" and args 
"{"capabilities":{"alwaysMatch":{"browserName":"chrome","browserVersion":"134.0.6998.44","wdio:electronServiceOptions":
{"appBinaryPath":"C:\\Perso\\myapp.exe"},"goog:chromeOptions":{"binary":"C:\\Perso\\myapp.exe","prefs":
{"profile.password_manager_leak_detection":false},"windowTypes":["app","webview"],"args":["--disable-dev-shm-usage","--disable-gpu","--headless","--no-sandbox","--inspect=localhost:58062"]},"wdio:enforceWebDriverClassic":true},"firstMatch":[{}]}}"
[chrome 134.0.6998.44 (unknown) #0-0]


Spec Files:      0 passed, 1 failed, 1 total (100% completed) in 00:00:08

2025-08-14T18:16:37.451Z INFO @wdio/local-runner: Shutting down spawned worker
2025-08-14T18:16:37.702Z INFO @wdio/local-runner: Waiting for 0 to shut down gracefully
2025-08-14T18:16:37.703Z INFO @wdio/local-runner: shutting down
2025-08-14T18:16:37.703Z INFO @wdio/cli:launcher: Run onComplete hook
2025-08-14T18:16:37.704Z DEBUG @wdio/cli:utils: Finished to run "onComplete" hook in 0ms

Here is my WDIO config excerpt

export const config: WebdriverIO.Config = {
    runner: 'local',
    tsConfigPath: './tsconfig.json',
    
    specs: [
        './features/*.feature'
    ],
    // Patterns to exclude.
    exclude: [
        // 'path/to/excluded/files'
    ],

    maxInstances: 1,

    capabilities: [{
        browserName: 'electron',
        browserVersion: '35.0.0',

        'wdio:electronServiceOptions': {
            // custom application args
            appBinaryPath: process.env.MYAPP_EXE!,
        },
    }],

    logLevel: 'trace',

    bail: 0,
    waitforTimeout: 10000,
    connectionRetryTimeout: 120000,
    connectionRetryCount: 3,

    services: ['electron'],

    cucumberOpts: {
        // <string[]> (file/dir) require files before executing features
        require: ['./steps/definitions/**/*.ts'],
        // <boolean> show full backtrace for errors
        backtrace: false,
        // <string[]> ("extension:module") require files with the given EXTENSION after requiring MODULE (repeatable)
        requireModule: [],
        // <boolean> invoke formatters without executing steps
        dryRun: false,
        // <boolean> abort the run on first failure
        failFast: false,
        // <string[]> Only execute the scenarios with name matching the expression (repeatable).
        name: [],
        // <boolean> hide step definition snippets for pending steps
        snippets: true,
        // <boolean> hide source uris
        source: true,
        // <boolean> fail if there are any undefined or pending steps
        strict: true,
        // <string> (expression) only execute the features or scenarios with tags matching the expression
        tagExpression: '',
        // <number> timeout for step definitions
        timeout: 60000,
        // <boolean> Enable this config to treat undefined definitions as warnings.
        ignoreUndefinedDefinitions: false
    },

What I already tried

Changing/removing --inspect arg / using ephemeral port
Fresh --user-data-dir per run (with Date.now())
Aligning versions of Electron/Chromium ↔ ChromeDriver
Increasing startup/connection timeouts

What I observed

The app does launch, but only after the WDIO process exits.
If maxRetries is 0, the app launches after the terminal closes (so no tests run).
If retries > 0, the app sometimes opens mid-retry (e.g., on the 5th attempt), which I think it means it’s already starting at the first try but not being detected.

Packages Version

"devDependencies": {
    "@types/node": "^24.1.0",
    "@wdio/cli": "^9.18.4",
    "@wdio/cucumber-framework": "^9.18.0",
    "@wdio/globals": "^9.17.0",
    "@wdio/local-runner": "^9.18.4",
    "@wdio/spec-reporter": "^9.18.0",
    "electron": "^35.0.0",
    "gojs": "^3.0.24",
    "ts-node": "^10.9.2",
    "typescript": "5.8",
    "wdio-electron-service": "^8.2.1"
  }

I haven’t yet found a plausible solution; do you have an idea what is going on?
Thank you!

christian-bromann · 2025-08-24T04:49:23Z

christian-bromann
Aug 24, 2025
Maintainer

@minh-de-rien I recommend to raise an issue in the Electron Service project.

0 replies

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christian-bromann Aug 24, 2025 Maintainer

minh-de-rien
Aug 15, 2025

christian-bromann
Aug 24, 2025
Maintainer