# Build failed with Build script returned non-zero exit code: 4 **URL:** \ **Category:** Support\ **Tags:** building, deployment\ **Created:** [December 12, 2023, 11:26pm UTC](https://answers.netlify.com/t/build-failed-with-build-script-returned-non-zero-exit-code-4/108506 "2023-12-12T23:26:55Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![garethf](https://sea1.discourse-cdn.com/netlify/user_avatar/answers.netlify.com/garethf/32/23544_2.png) [@garethf](https://answers.netlify.com/u/garethf)\ **Post date:** [December 12, 2023, 11:26pm UTC](https://answers.netlify.com/t/build-failed-with-build-script-returned-non-zero-exit-code-4/108506/1 "2023-12-12T23:26:55Z")
Hi, I am getting the error `Build script returned non-zero exit code: 4` on a build task that actually builds correctly. This exact repo was used to build a website a week ago on another Netlify site and worked correcly with the same env variables and settings. I know it’s old versions of Node and Gatsby etc. but they still should build and deploy. Can anyone please help with this? Log: ```auto 10:53:19 PM: build-image version: 3ffff9df3d5419545acc1b673a54de348174406d (focal) 10:53:19 PM: buildbot version: 06bd328e5eb3b6956f9c6602486ecccce8b861a0 10:53:19 PM: Fetching cached dependencies 10:53:19 PM: Failed to fetch cache, continuing with build 10:53:19 PM: Starting to prepare the repo for build 10:53:19 PM: No cached dependencies found. Cloning fresh repo 10:53:20 PM: Preparing Git Reference refs/heads/master 10:53:21 PM: Starting to install dependencies 10:53:21 PM: Python version set to 3.8 10:53:21 PM: Attempting Ruby version 2.7.2, read from environment 10:53:22 PM: Using Ruby version 2.7.2 10:53:23 PM: Started restoring cached go cache 10:53:23 PM: Finished restoring cached go cache 10:53:24 PM: go version go1.19.13 linux/amd64 10:53:24 PM: Using PHP version 8.0 10:53:25 PM: Downloading and installing node v14.21.3... 10:53:26 PM: Downloading https://nodejs.org/dist/v14.21.3/node-v14.21.3-linux-x64.tar.xz... 10:53:26 PM: Computing checksum with sha256sum 10:53:26 PM: Checksums matched! 10:53:28 PM: Now using node v14.21.3 (npm v6.14.18) 10:53:28 PM: Enabling Node.js Corepack 10:53:28 PM: Started restoring cached build plugins 10:53:28 PM: Finished restoring cached build plugins 10:53:28 PM: Started restoring cached corepack dependencies 10:53:28 PM: Finished restoring cached corepack dependencies 10:53:28 PM: Started restoring cached yarn cache 10:53:28 PM: Finished restoring cached yarn cache 10:53:28 PM: No yarn workspaces detected 10:53:28 PM: Started restoring cached node modules 10:53:28 PM: Finished restoring cached node modules 10:53:28 PM: Installing npm packages using Yarn version 1.22.19 10:53:29 PM: yarn install v1.22.19 10:53:29 PM: [1/4] Resolving packages... 10:53:29 PM: [2/4] Fetching packages... 10:53:34 PM: warning url-loader@1.1.2: Invalid bin field for "url-loader". 10:54:00 PM: [3/4] Linking dependencies... 10:54:00 PM: warning "gatsby > @pmmmwh/react-refresh-webpack-plugin@0.3.3" has incorrect peer dependency "react-refresh@^0.8.2". 10:54:00 PM: warning " > babel-loader@8.1.0" has unmet peer dependency "webpack@>=2". 10:54:00 PM: warning "gatsby > @typescript-eslint/eslint-plugin > tsutils@3.17.1" has unmet peer dependency "typescript@>=2.8.0 || >= 3.2.0-dev || >= 3.3.0-dev || >= 3.4.0-dev || >= 3.5.0-dev || >= 3.6.0-dev || >= 3.6.0-beta || >= 3.7.0-dev || >= 3.7.0-beta". 10:54:00 PM: warning "gatsby > gatsby-admin > gatsby-interface@0.0.163" has incorrect peer dependency "gatsby@2.6.0". 10:54:00 PM: warning "gatsby > gatsby-admin > gatsby-interface@0.0.163" has incorrect peer dependency "react@16.8.1". 10:54:00 PM: warning "gatsby > gatsby-admin > gatsby-interface@0.0.163" has incorrect peer dependency "react-dom@16.8.1". 10:54:00 PM: warning "gatsby > gatsby-admin > gatsby-interface@0.0.163" has incorrect peer dependency "yup@^0.27.0". 10:54:00 PM: warning "gatsby-plugin-netlify > webpack-assets-manifest@3.1.1" has unmet peer dependency "webpack@>=4.4.0". 10:54:00 PM: warning " > gatsby-plugin-theme-ui@0.3.0" has incorrect peer dependency "theme-ui@^0.2.0". 10:54:00 PM: warning "@storybook/addon-a11y > @storybook/api@5.3.19" has unmet peer dependency "regenerator-runtime@*". 10:54:00 PM: warning " > eslint-config-gatsby-standard@2.2.0" has incorrect peer dependency "eslint@^5.16.0". 10:54:00 PM: warning "eslint-config-gatsby-standard > eslint-plugin-react@7.19.0" has incorrect peer dependency "eslint@^3.0.0 || ^4.0.0 || ^5.0.0 || ^6.0.0". 10:54:28 PM: [4/4] Building fresh packages... 10:54:45 PM: Done in 76.34s. 10:54:45 PM: npm packages installed using Yarn 10:54:45 PM: Successfully installed dependencies 10:54:45 PM: Starting build script 10:54:46 PM: Detected 1 framework(s) 10:54:46 PM: "gatsby" at version "2.22.13" 10:54:46 PM: Section completed: initializing 10:54:48 PM: ​ 10:54:48 PM: Netlify Build 10:54:48 PM: ──────────────────────────────────────────────────────────────── 10:54:48 PM: ​ 10:54:48 PM: ❯ Version 10:54:48 PM: @netlify/build 29.31.0 10:54:48 PM: ​ 10:54:48 PM: ❯ Flags 10:54:48 PM: baseRelDir: true 10:54:48 PM: buildId: 6578e45c97fa131d7013e381 10:54:48 PM: deployId: 6578e45c97fa131d7013e383 10:54:48 PM: ​ 10:54:48 PM: ❯ Current directory 10:54:48 PM: /opt/build/repo 10:54:48 PM: ​ 10:54:48 PM: ❯ Config file 10:54:48 PM: No config file was defined: using default values. 10:54:48 PM: ​ 10:54:48 PM: ❯ Context 10:54:48 PM: production 10:54:48 PM: ​ 10:54:48 PM: ❯ Installing plugins 10:54:48 PM: - @netlify/plugin-gatsby@3.8.0 10:55:05 PM: ​ 10:55:05 PM: ❯ Loading plugins 10:55:05 PM: - @netlify/plugin-gatsby@3.8.0 from Netlify app 10:55:06 PM: ​ 10:55:06 PM: @netlify/plugin-gatsby (onPreBuild event) 10:55:06 PM: ──────────────────────────────────────────────────────────────── 10:55:06 PM: ​ 10:55:06 PM: No Gatsby cache found. Building fresh. 10:55:06 PM: The plugin `gatsby-plugin-netlify` does not support DSG, please update to >=4.2.0 10:55:06 PM: ​ 10:55:06 PM: (@netlify/plugin-gatsby onPreBuild completed in 12ms) 10:55:06 PM: ​ 10:55:06 PM: Build command from Netlify app 10:55:06 PM: ──────────────────────────────────────────────────────────────── 10:55:06 PM: ​ 10:55:06 PM: $ CI="" yarn previewSetup && yarn run build:preview 10:55:06 PM: yarn run v1.22.19 10:55:06 PM: $ cp -f preview.toml netlify.toml 10:55:06 PM: Done in 0.04s. 10:55:07 PM: yarn run v1.22.19 10:55:07 PM: $ gatsby build 10:55:08 PM: success open and validate gatsby-configs - 0.033s 10:55:09 PM: success load plugins - 0.430s 10:55:09 PM: success onPreInit - 0.007s 10:55:09 PM: success delete html and css files from previous builds - 0.008s 10:55:09 PM: success initialize cache - 0.004s 10:55:09 PM: success copy gatsby files - 0.017s 10:55:09 PM: success onPreBootstrap - 0.005s 10:55:09 PM: info Reading GraphQL type definitions from /opt/build/repo/src/gatsby/schema/schema.gql 10:55:09 PM: success createSchemaCustomization - 0.009s 10:55:09 PM: Starting to fetch data from Contentful 10:55:09 PM: info Fetching default locale 10:55:09 PM: info default locale is: en-GB 10:55:10 PM: info contentTypes fetched 10 10:55:10 PM: info Updated entries 67 10:55:10 PM: info Deleted entries 0 10:55:10 PM: info Updated assets 72 10:55:10 PM: info Deleted assets 0 10:55:10 PM: Fetch Contentful data: 657.726ms 10:55:10 PM: success source and transform nodes - 0.920s 10:55:10 PM: success building schema - 0.438s 10:55:10 PM: success createPages - 0.026s 10:55:10 PM: success createPagesStatefully - 0.043s 10:55:10 PM: success onPreExtractQueries - 0.001s 10:55:10 PM: success update schema - 0.015s 10:55:11 PM: success extract queries from components - 0.329s 10:55:11 PM: success write out requires - 0.005s 10:55:11 PM: success write out redirect data - 0.001s 10:55:11 PM: success Build manifest and related icons - 0.138s 10:55:11 PM: success onPostBootstrap - 0.139s 10:55:11 PM: ⠀ 10:55:11 PM: info bootstrap finished - 3.998s 10:55:11 PM: ⠀ 10:55:11 PM: warning Browserslist: caniuse-lite is outdated. Please run: 10:55:11 PM: npx browserslist@latest --update-db 10:55:29 PM: success Building production JavaScript and CSS bundles - 17.782s 10:55:29 PM: success Rewriting compilation hashes - 0.001s 10:55:29 PM: success run queries - 18.328s - 21/21 1.15/s 10:55:32 PM: success Building static HTML for pages - 2.903s - 13/13 4.48/s 10:55:32 PM: success Generating image thumbnails - 21.273s - 2/2 0.09/s 10:55:32 PM: success onPostBuild - 0.005s 10:55:32 PM: info Done building in 25.291605932 sec 10:55:32 PM: Done in 25.56s. 10:55:32 PM: Unhandled rejection… 10:55:32 PM: TypeError: Cannot read properties of undefined (reading "packageName") 10:55:32 PM: at title (file:///opt/buildhome/node-deps/node_modules/@netlify/build/lib/error/types.js:281:31) 10:55:32 PM: at getTitle (file:///opt/buildhome/node-deps/node_modules/@netlify/build/lib/error/parse/parse.js:69:12) 10:55:32 PM: at getFullErrorInfo (file:///opt/buildhome/node-deps/node_modules/@netlify/build/lib/error/parse/parse.js:14:20) 10:55:32 PM: at logBuildError (file:///opt/buildhome/node-deps/node_modules/@netlify/build/lib/log/messages/core.js:17:27) 10:55:32 PM: at handleBuildError (file:///opt/buildhome/node-deps/node_modules/@netlify/build/lib/error/handle.js:17:9) 10:55:32 PM: at async file:///opt/buildhome/node-deps/node_modules/@netlify/build/lib/core/main.js:81:34 10:55:32 PM: at async buildSite (file:///opt/buildhome/node-deps/node_modules/@netlify/build/lib/core/main.js:31:12) 10:55:32 PM: at async runCli (file:///opt/buildhome/node-deps/node_modules/@netlify/build/lib/core/bin.js:22:36) 10:55:32 PM: /opt/buildhome/node-deps/node_modules/.bin/netlify-build exited with exit code 0 without finishing the build. 10:55:33 PM: Build failed due to an internal system error: Build script returned non-zero exit code: 4 10:55:33 PM: Failing build: Failed to build site 10:55:33 PM: Finished processing build request in 2m14.126s 10:55:33 PM: Failed during stage "building site": Build script returned non-zero exit code: 4 ``` ---
**Author:** ![SamO](https://sea1.discourse-cdn.com/netlify/user_avatar/answers.netlify.com/samo/32/41847_2.png) [@SamO](https://answers.netlify.com/u/SamO)\ **Post date:** [December 14, 2023, 6:57pm UTC](https://answers.netlify.com/t/build-failed-with-build-script-returned-non-zero-exit-code-4/108506/2 "2023-12-14T18:57:00Z")
what site are you writing in about? ---
**Author:** ![garethf](https://sea1.discourse-cdn.com/netlify/user_avatar/answers.netlify.com/garethf/32/23544_2.png) [@garethf](https://answers.netlify.com/u/garethf)\ **Post date:** [December 18, 2023, 10:58am UTC](https://answers.netlify.com/t/build-failed-with-build-script-returned-non-zero-exit-code-4/108506/3 "2023-12-18T10:58:08Z")
@SamO Thanks for the response, it is [alex-preview.netlify.app](https://alex-preview.netlify.app) ---
**Author:** ![Melvin](https://sea1.discourse-cdn.com/netlify/user_avatar/answers.netlify.com/melvin/32/23606_2.png) [@Melvin](https://answers.netlify.com/u/Melvin)\ **Post date:** [December 18, 2023, 6:47pm UTC](https://answers.netlify.com/t/build-failed-with-build-script-returned-non-zero-exit-code-4/108506/4 "2023-12-18T18:47:09Z")
Hi @garethf, Thanks for the follow-up. Looks like the error is here: [https://app.netlify.com/sites/alex-preview/deploys/6578e7a15f54ec1fc0bfc789#L147](https://app.netlify.com/sites/alex-preview/deploys/6578e7a15f54ec1fc0bfc789#L147) I believe the error lies with the code. This error occurs when a property is read or a function is called on an undefined variable. Have you declared that variable but not used it in your code anywhere? This Support Guide has a lot of debugging tips that may help: > [@\[Support Guide\] Frequently encountered problems during builds](https://answers.netlify.com/t/support-guide-frequently-encountered-problems-during-builds/213): > > Last reviewed by Netlify Support - July 2025 Overview Sites on Netlify can be built using a variety of tools — different frameworks, programming languages and approaches. It can be incredibly frustrating to see your site fail to build! If you have a build on Netlify that is failing with an error message that you don’t understand, you are not alone. Here you’ll find some common build failure messages, and probable solutions to their causes. If you’re looking for more general information on build… If you’re still having issues, please let us know if you’re able to deploy locally. ---
**Author:** ![garethf](https://sea1.discourse-cdn.com/netlify/user_avatar/answers.netlify.com/garethf/32/23544_2.png) [@garethf](https://answers.netlify.com/u/garethf)\ **Post date:** [December 20, 2023, 11:08pm UTC](https://answers.netlify.com/t/build-failed-with-build-script-returned-non-zero-exit-code-4/108506/5 "2023-12-20T23:08:45Z")
@Melvin Thanks for the response, this error was actually being caused by the netlify.toml file I was generating on build time to hide this site from search engines. I couldn’t see anything wrong with the syntax but this was causing the error. Are there any settings in Netlify to keep this private? ---
**Author:** ![Melvin](https://sea1.discourse-cdn.com/netlify/user_avatar/answers.netlify.com/melvin/32/23606_2.png) [@Melvin](https://answers.netlify.com/u/Melvin)\ **Post date:** [December 21, 2023, 1:15pm UTC](https://answers.netlify.com/t/build-failed-with-build-script-returned-non-zero-exit-code-4/108506/6 "2023-12-21T13:15:41Z")
Hi @garethf, Thanks for following up. Do you mean to keep this form post private or do you mean to keep your site private? ---
**Author:** ![matthew-peterson-39](https://sea1.discourse-cdn.com/netlify/user_avatar/answers.netlify.com/matthew-peterson-39/32/67216_2.png) [@matthew-peterson-39](https://answers.netlify.com/u/matthew-peterson-39)\ **Post date:** [January 30, 2025, 3:12pm UTC](https://answers.netlify.com/t/build-failed-with-build-script-returned-non-zero-exit-code-4/108506/7 "2025-01-30T15:12:39Z")
I experienced this issue earlier today. I was able to solve it by running the build command on the branch that was experiencing the issue, for me it was ‘npm run build’, pushed these changes and then redployed without any issue. Hopefully this helps others in the same boat!