Expo EAS Build iOS: EACCES: permission denied, mkdir 'node_modules' — tried everything, still stuck!

[shahbaz242630]

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Context:

I’m working on an Expo + React Native project (expo-router, nativewind, etc.), trying to build for iOS using EAS Build cloud services.

When triggering a build using:

eas build --platform ios --profile development-device

…the build fails consistently with this error:

npm error code EACCES
npm error syscall mkdir
npm error path /Users/expo/workingdir/build/Sage/node_modules
npm error Error: EACCES: permission denied, mkdir '/Users/expo/workingdir/build/Sage/node_modules'

✅ What I’ve tried so far:

Switched from npm to yarn:

Error still occurs: EACCES: permission denied, mkdir '/Users/expo/workingdir/build/Sage/node_modules'

Added the following env vars to eas.json (under development-device.ios.env):

"env": {
"NPM_CONFIG_UNSAFE_PERM": "true",
"npm_config_unsafe_perm": "true"
}

Added a eas-build-pre-install.js script to manually change permissions and install dependencies:

const { execSync } = require("child_process");

console.log("🔧 Fixing permissions and installing dependencies...");

try {
execSync("sudo chown -R $(whoami) .", { stdio: "inherit" });
} catch (error) {
console.log("⚠️ Could not change ownership, continuing...");
}

execSync("rm -rf node_modules", { stdio: "inherit" });
execSync("npm install --legacy-peer-deps --unsafe-perm=true", { stdio: "inherit" });

Confirmed I’m not using private packages

Ran expo-doctor and fixed all issues except some known unmaintained packages

Expo support asked me to try local iOS build, but I’m on Windows, so I cannot run:

eas build --platform ios --profile development-device --local

🧪 Other details:

The same build works fine when using the development profile (without developmentClient).

Only iOS builds fail with the permission error.

App builds fine locally (Android + iOS dev mode via simulator).

No issues with lockfiles or node_modules locally.

❓Question:

Has anyone seen this issue before with EAS iOS builds and node_modules permission errors? Is there something unique about the /Users/expo/workingdir/build/... environment that prevents mkdir?

Do I need to explicitly sudo something differently in eas-build-pre-install.js?

Is there an internal EAS bug or misconfiguration?

Any recent changes to how iOS cloud workers are provisioned?

Any tips, suggestions, or workarounds would be massively appreciated! 🙏

[ikrishanaa]

Hi ,

This looks like an environment-specific permissions issue with EAS iOS build workers rather than your project setup. The path /Users/expo/workingdir/build/... is a sandboxed environment and sudo or chown inside eas-build-pre-install.js wont persist or affect that root permission layer. That’s why the EACCES: permission denied, mkdir 'node_modules' keeps reappearing.

What usually helps: Clean install via cache disable
In your eas.json add:

{
  "build": {
    "development-device": {
      "ios": {
        "env": {
          "CI": "1",
          "NPM_CONFIG_CACHE": "false"
        },
        "cache": {
          "disabled": true
        }
      }
    }
  }
}

This forces EAS to reinstall node_modules in a fresh temp dir instead of hitting a cached layer with bad perms.

Switch to Yarn / PNPM without sudo
Yarn (yarn install --immutable) or PNPM are safer in EAS than npm --unsafe-perm, since sudo isn’t available on cloud runners.

Prebuild instead of during build
Run expo prebuild locally commit the native ios/ and android/ folders, then let EAS build without generating node_modules at runtime. This bypasses the mkdir issue entirely.

Known workaround
Some teams add:

"postinstall": "expo-yarn-workspaces clean && expo-yarn-workspaces check"
in package.json -- ensuring dependencies are installed in user-space paths, not root-owned paths.

Recommendation:
Try disabling cache in eas.json and switch to Yarn/PNPM for dependency installation. If the error still occurs, prebuild locally and commit native files so node_modules dont need to be generated at build time.

If none of these work, I’d raise it as an EAS worker bug report with Expo support, since the mkdir permissions at /Users/expo/workingdir should be writable by default.

[shahbaz242630]

Thank you ... ikrishanaa . Tried but not working ...
fails with below log .

Running "yarn install --frozen-lockfile" in /Users/expo/workingdir/build/Sage directory
Thu, 21 Aug 2025 10:41:58 GMT

yarn install v1.22.22
Thu, 21 Aug 2025 10:41:58 GMT

warning package-lock.json found. Your project contains lock files generated by tools other than Yarn. It is advised not to mix package managers in order to avoid resolution inconsistencies caused by unsynchronized lock files. To clear this warning, remove package-lock.json.
Thu, 21 Aug 2025 10:41:58 GMT

[1/4] Resolving packages...
Thu, 21 Aug 2025 10:41:59 GMT

[2/4] Fetching packages...
Thu, 21 Aug 2025 10:42:15 GMT

[3/4] Linking dependencies...
Thu, 21 Aug 2025 10:42:15 GMT

warning " > [email protected]" has unmet peer dependency "tailwindcss@>3.3.0".
Thu, 21 Aug 2025 10:42:15 GMT

warning "nativewind > [email protected]" has unmet peer dependency "tailwindcss@~3".
Thu, 21 Aug 2025 10:42:15 GMT

warning " > [email protected]" has unmet peer dependency "@react-native-masked-view/masked-view@^0.2.8".
Thu, 21 Aug 2025 10:42:15 GMT

warning " > [email protected]" has unmet peer dependency "react-native-linear-gradient@^2.5.6".
Thu, 21 Aug 2025 10:42:15 GMT

warning "jest-expo > [email protected]" has unmet peer dependency "webpack@^5.59.0".
Thu, 21 Aug 2025 10:42:15 GMT

warning Workspaces can only be enabled in private projects.
Thu, 21 Aug 2025 10:42:15 GMT

warning Workspaces can only be enabled in private projects.
Thu, 21 Aug 2025 10:42:15 GMT

warning Workspaces can only be enabled in private projects.
Thu, 21 Aug 2025 10:42:15 GMT

error Error: EACCES: permission denied, mkdir '/Users/expo/workingdir/build/Sage/node_modules'
Thu, 21 Aug 2025 10:42:15 GMT

info Visit https://yarnpkg.com/en/docs/cli/install for documentation about this command.
Thu, 21 Aug 2025 10:42:15 GMT

yarn install --frozen-lockfile exited with non-zero code: 1

Fail job

1s

Thu, 21 Aug 2025 10:42:15 GMT

Build failed

yarn install --frozen-lockfile exited with non-zero code: 1

[ikrishanaa]

in your shared logs

it looks like this isn’t a dependency issue but a permissions bug on the EAS iOS worker (mkdir node_modules should never fail)

The key point here is that the error happens at the mkdir node_modules step itself -- before Yarn/npm even starts linking. That means it’s not a lockfile / dependency issue, but rather a permissions issue on the Expo iOS build worker (/Users/expo/workingdir/build/Sage).

At this point-
Mixing package-lock.json + yarn.lock can be ignored — it’s not the root cause.
peerDependencies warnings are normal noise.

Next things to try:
Delete package-lock.json (stick with Yarn only).
In eas.json, explicitly disable cache for iOS builds:

"cache": { "disabled": true }

--This forces EAS to rebuild node_modules in a fresh sandbox each time.
if it still fails, run expo prebuild locally, commit the ios/ folder, and push - this avoids node_modules being created during the build itself.

If none of these work , this really points to an Expo EAS macOS worker bug, since node_modules should be writable by default. In that case, I’d recommend opening a bug ticket with Expo support and linking this log, because no amount of sudo or env vars in pre-install can override sandbox permissions.

[shahbaz242630]

great thank you

[Niharika07-B]

Yes, this is a known issue with EAS iOS builds where a permission conflict prevents the build from creating the node_modules directory. The error, EACCES: permission denied, mkdir, means the build process doesn't have the necessary write permissions.

Why It Happens

The EAS build for iOS runs on a dedicated macOS virtual machine. The user is expo, and the working directory is /Users/expo/workingdir/build/. While the environment is generally well-configured, a previous build step or cache issue can sometimes leave the project directory with incorrect permissions, preventing the package manager (like npm or yarn) from creating the node_modules folder. This is why the error is inconsistent and often only affects specific build profiles or platforms.

The Solution: A Pre-Install Script

The most reliable solution is to explicitly adjust the directory permissions before the dependency installation begins. Your attempt with eas-build-pre-install.js was correct, but it can be made more robust to work in the specific EAS cloud environment.

Here is an improved eas-build-pre-install.js script:

const { execSync } = require('child_process');

console.log("🔧 Forcing ownership and permissions before npm install...");

// Change ownership of the build directory to the 'expo' user.
// This ensures the user running the build has full control.
execSync("sudo chown -R expo:staff /Users/expo/workingdir/build", { stdio: "inherit" });

// Grant full read, write, and execute permissions to all users.
// This is a safe practice in the isolated, single-use EAS environment.
execSync("sudo chmod -R 777 /Users/expo/workingdir/build", { stdio: "inherit" });

console.log("✅ Permissions adjusted successfully.");

// Now, proceed with your original commands to clean and install.
execSync("rm -rf node_modules", { stdio: "inherit" });
execSync("npm install --legacy-peer-deps --unsafe-perm=true", { stdio: "inherit" });

console.log("📦 Dependencies installed successfully.");

---

Steps to Implement the Solution

1. Create the Script: Save the code above into a file named eas-build-pre-install.js in the root directory of your project.
2. Update package.json: Add the script to your package.json file. This tells EAS Build to run the script automatically before installing dependencies.

"scripts": {
  "eas-build-pre-install": "node ./eas-build-pre-install.js"
}

By adding this script, you are guaranteeing that the build environment has the necessary permissions to create the node_modules directory, effectively bypassing the EACCES error and allowing the build to proceed correctly.

[Niharika07-B]

Firstly,I’m glad it’s working with the solution I shared & really happy it helped!

As you aksed follow these....

Step 1: Fix Multiple Lock Files*

Problem:
You have both yarn.lock and package-lock.json. EAS Build gets confused about which package manager to use.

Why fix it:

• Ensures consistent dependencies across builds.
• Prevents weird build errors on EAS.

How to fix:

1. Decide which package manager you are using:

   • Yarn → keep yarn.lock, delete package-lock.json
   • npm → keep package-lock.json, delete yarn.lock

2. Run the delete command in your project folder:

# If using yarn
rm package-lock.json

# If using npm
rm yarn.lock

---

Step 2: Install Missing Peer Dependency

Problem:

Missing peer dependency: @react-native-masked-view/masked-view
Required by: react-native-skeleton-placeholder

Why fix it:

• Without this, your app may crash outside Expo Go.
• Peer dependencies are required by some libraries to work properly.

How to fix:
Run this command in your project:

npx expo install @react-native-masked-view/masked-view

After this, the dependency will be installed and the warning should disappear.

---

Step 3: Handle App Config Fields in Native Folders

Problem:
Your project has /android and /ios folders, but also has config in app.config.js. EAS Build may ignore some settings like icons or orientation.

Why fix it:

• Ensures that app behaves as expected (icon, orientation, splash screens).

How to fix:
You have two options:

Option A: Use Prebuild / CNG workflow

• Add /android and /ios to .gitignore
• Let EAS Build generate native folders automatically

Option B: Keep native folders

• Remove the same properties from app.config.js
• Set them directly in Xcode (iOS) or AndroidManifest (Android)

---

Step 4: React Native Directory Warnings

Problem:
Some libraries are unmaintained, untested, or lack metadata:

• react-native-skeleton-placeholder → unmaintained
• react-native-iap → untested on New Architecture
• dotenv, loglevel, uuid → no metadata

Why fix it:

• Mostly informational.
• May cause problems if a library is incompatible with future React Native versions.

How to fix:

• Option 1: Replace unmaintained libraries with alternatives.
• Option 2: Ignore warnings if the libraries work fine:

Add this in your package.json:

{
  "expo": {
    "doctor": {
      "reactNativeDirectoryCheck": {
        "exclude": ["react-native-skeleton-placeholder", "react-native-iap"]
      }
    }
  }
}

---

✅ Step 5: Run Expo Doctor Again

After all fixes, run:

npx expo doctor

You should now see all green ticks or only minor warnings.

[shahbaz242630]

thank you ... what will you recommend with my current setup .. yarn or npm ? appreciate your guidance.

[shahbaz242630]

between thank you so much for providing fix for expo doctor .... all issues resolved all green ticks... really appreciate it

[Niharika07-B]

between thank you so much for providing fix for expo doctor .... all issues resolved all green ticks... really appreciate it

can you please accept my answer
to get an achievement😅

[shahbaz242630]

oh yes sorry I have marked ... sorry I am new to all this ... I have now marked your answer.