Rork App Won't Build? Beginner Common Error FAQ

Starting with Rork is exciting, but build errors can quickly turn enthusiasm into frustration. If you're new to app development, error messages can feel cryptic and overwhelming. This FAQ addresses the seven most common build errors that Rork beginners encounter and provides clear, actionable solutions for each.

Q1: I'm Getting "Build Failed" Errors. What Are Dependency Conflicts?

A: A "Build Failed" message typically indicates a dependency conflict—when different packages in your project require incompatible versions of the same library.

What's a Dependency Conflict?

Your project relies on multiple packages, and they can have conflicting version requirements. For example, Package A might require Library X version 1.0, while Package B requires Library X version 2.0. When npm tries to satisfy both requirements, it creates a conflict.

The Solution

# Step 1: Delete node_modules and package-lock.json
rm -rf node_modules package-lock.json
 
# Step 2: Clear npm cache
npm cache clean --force
 
# Step 3: Reinstall dependencies
npm install

:::tip If npm install still fails, try npm install --legacy-peer-deps. This allows older dependency versions to work together. :::

Diagnose Further

Read the error messages carefully. If you see "conflicting peer dependency," you may need to update a specific package version.

# Update a specific package
npm install package-name@latest

Q2: "Expo Module Not Found" Error

A: This error means Expo's dependencies aren't properly installed in your project.

Causes and Fixes

Cause 1: Expo isn't installed

# Install Expo CLI globally
npm install -g expo-cli
 
# Or install locally in your project
npm install expo

Cause 2: Expo version is outdated

# Update Expo to the latest version
npm install expo@latest

Cause 3: Dependencies didn't install completely

# Reinstall using npm ci (more reliable than npm install)
npm ci

:::warning npm ci is different from npm install. It installs exact versions from package-lock.json, making it more reliable for clean installs. :::

Verify Expo Works

After installing, check that Expo is working correctly:

expo --version

If a version number displays, you're good to go.

Q3: iOS Simulator Won't Start

A: iOS simulator startup failures usually have a few common causes.

Cause 1: Xcode Not Installed (macOS Only)

Xcode is required for iOS development.

# Install from App Store or command line tools
xcode-select --install

Cause 2: Simulator Doesn't Exist

# List available simulators
xcrun simctl list devices
 
# Boot a simulator (e.g., iPhone 15 Pro)
xcrun simctl boot "iPhone 15 Pro"

Cause 3: Port Conflict

Another process may be using the port the simulator needs.

# Check what's using port 8081
lsof -i :8081
 
# Kill the process
kill -9 <PID>
 
# Run Rork on a different port
expo start -p 8082

:::tip Using Expo Go with your physical iPhone avoids simulator issues entirely—a great option for beginners. :::

Q4: Android Emulator Shows Blank White Screen

A: The blank white screen issue is frustrating, but it's usually fixable with a few troubleshooting steps.

Causes and Fixes

Cause 1: App isn't fully built

# Reset and rebuild
expo start --clear

When you see "Watching for file changes" in the terminal, press r in the emulator to reload.

Cause 2: Java SDK version is wrong

Android development requires Java SDK (JDK). Make sure the right version is installed.

# Check Java version
java -version
 
# Install JDK if missing
# macOS: brew install openjdk@11
# Windows: Download from https://www.oracle.com/java/technologies/downloads/

**Cause 3: Emulator doesn't have enough RAM

The Android Virtual Device (AVD) may not have enough memory allocated.

• Open Android Studio
• Open AVD Manager
• Edit your emulator
• Increase RAM to at least 2048 MB

Cause 4: Network connectivity is broken

The Android emulator needs network connection to the host machine.

# Restart the emulator
emulator -avd <AVD_NAME>
 
# Or use Expo Go on a physical device

:::warning If the white screen persists, carefully read the terminal error messages—they usually point to the exact fix needed. :::

Q5: App Generation Freezes or Doesn't Start

A: When Rork's AI freezes during app generation, it's usually because your prompt is too complex or system resources are depleted.

Causes and Fixes

Cause 1: Prompt is too complex

Very long or complex prompts (3000+ characters) can cause timeouts.

Fix:

• Keep prompts concise (1000–1500 characters)
• Split complex requests into multiple steps
• Start with basic features, refine later

// Bad example (too complex)
"Build a chat app with real-time notifications, user profile images,
message search, group chats, voice messages, video calls,
blocking, read receipts, ..."

// Good example (simple)
"Build a chat app where users can send and receive messages.
Keep the UI simple."

Cause 2: Internet connection is unstable

Network drops during generation cause freezes.

Fix:

• Verify stable WiFi
• Check browser console (F12) for errors
• Stop and retry the generation

Cause 3: Browser running out of resources

Too many tabs or other apps consuming memory.

Fix:

• Close unnecessary browser tabs
• Close other applications to free memory
• Clear browser cache

:::tip If generation stalls, use the browser's back button and retry with a simpler prompt. :::

Q6: Images and Icons Don't Display

A: Missing images or icons usually stem from incorrect file paths or missing asset folders.

Causes and Fixes

Cause 1: Image path is wrong

Rork's generated code may have incorrect relative paths.

// Wrong
<Image source={require('../assets/images/my-image.png')} />
 
// Right
<Image source={require('../../assets/images/my-image.png')} />

Cause 2: Asset folders don't exist

The assets or images folder might be missing from your project.

Fix:

# Create assets folder
mkdir -p assets/images
 
# Add your image files there

Cause 3: Icon library not installed properly

Rork uses icon libraries like expo-vector-icons.

# Install vector icons
npm install expo-vector-icons

Cause 4: Cache is stale

Browser or emulator cache may be showing old images.

Fix:

# Clear cache and rebuild
expo start --clear
 
# Or
expo start -c

:::warning Use only alphanumeric characters and underscores in image filenames. Spaces or special characters can break paths. :::

Q7: Hot Reload Isn't Working—Changes Don't Appear

A: Hot reload automatically updates your app when you change code. When it stops working, there are several likely causes.

Causes and Fixes

Cause 1: Hot reload is disabled

Hot reload is usually on by default, but verify it's enabled:

# Start Expo with hot reload explicitly enabled
expo start --hot

Cause 2: File isn't saved

Changes don't appear if you haven't saved the file.

Fix:

• Ensure the file is saved (check for unsaved indicators)
• Manually save with Ctrl+S or Cmd+S

Cause 3: Syntax error in your code

If you have a syntax error, hot reload fails and shows a red error box.

Fix:

• Read the error message carefully
• Fix the syntax error
• Hot reload resumes automatically

// Wrong (missing semicolon can cause issues)
const name = "Rork"
console.log(name)
 
// Right
const name = "Rork";
console.log(name);

Cause 4: Emulator connection dropped

Network connection between your computer and the emulator was lost.

Fix:

# Restart Expo
expo start
 
# Reload the app in the simulator/emulator
// iOS: Dev menu (Cmd+D) > Reload
// Android: Dev menu (Cmd+M) > Reload

Cause 5: React StrictMode causes double rendering

React StrictMode intentionally renders components twice in development, which can make hot reload feel slow.

Fix: This is normal behavior. In production, double rendering doesn't happen. Expect changes to appear 2–3 seconds after you save.

:::tip If hot reload fails, use the dev menu "Full Reload" option for a complete restart. :::

Q8: Is It Safe to Use the "Fix Now" Button That Appears on Errors?

A: When a build or runtime error occurs, Rork sometimes shows a Fix Now button right below the error. It passes the error message and the surrounding code to the AI and applies a suggested fix automatically.

What Fix Now Handles Well

• Syntax errors (unclosed brackets, missing semicolons, typos)
• Missing imports or references to functions that don't exist
• Type mismatches—anything where the error message states the cause plainly

For errors with a mechanically identifiable cause, a single press of Fix Now often resolves them. It's worth trying before you move on to the manual steps in Q1–Q7.

What Fix Now Struggles With

Some errors rarely clear up through Fix Now alone:

• Dependency conflicts (Q1)—these need a fresh npm install, not a code edit
• Simulators or emulators that won't start (Q3, Q4)—an environment problem, unrelated to your code
• Generation freezes (Q5)—caused by server-side state

Because these aren't "fix the code" problems, Fix Now can apply an off-target change.

Using It Safely

The approach I usually recommend:

1. Read the error message yourself first
2. For syntax or import errors, press Fix Now
3. Always review the diff it applies
4. If two presses in a row don't help, stop and switch to the Q1–Q7 steps

Fix Now is convenient, but pressing it repeatedly without reading the changes can let the AI rewrite unrelated areas and make things messier. Make "review the diff after each press" a habit, and you can rely on it with confidence.

Looking back

When you hit a build error in Rork, follow this approach:

1. Read the error message carefully — Rork and the terminal often provide clear solutions
2. Reset dependencies — Try npm cache clean --force and npm install
3. Clean the project state — Run expo start --clear
4. Reinstall node_modules — A last-resort that often works
5. Check official docs — Rork and Expo docs have more detailed information

Most beginner build errors resolve with these methods. If problems persist, reach out to the Rork community forum—provide details about your setup and tool versions for the best support.