Next.js 15.0.1 build fails right after project creation because the initial app can compile in development but break during the stricter production build pipeline when your local Node.js version, package manager state, or generated dependency tree does not match what Next.js 15 expects.

If you created a fresh project with Next.js 15.0.1 and npm run build immediately fails, the issue is usually not your application code. In most cases, the failure comes from an environment mismatch: an unsupported Node.js runtime, a corrupted dependency install, or differences between how development mode and production compilation evaluate the app.

Understanding the Root Cause

A newly created Next.js project runs two very different workflows:

• next dev prioritizes fast feedback and can tolerate some conditions that production will not.
• next build performs stricter validation, full bundling, route analysis, type checks in many setups, and server/client boundary evaluation.

With Next.js 15.0.1, build errors on a clean project are commonly tied to one of these technical causes:

1. Unsupported Node.js version
   Next.js 15 expects a modern Node runtime. If your machine is using an older version, the app may install but fail when the production build invokes newer runtime features.
2. Broken or stale dependency tree
   A partially resolved node_modules folder or an outdated package-lock.json can cause the generated project to build against package versions that do not align correctly.
3. Package manager inconsistency
   Creating the project with one package manager and building it after reinstalling with another can alter dependency resolution enough to trigger build-time failures.
4. Environment-specific build behavior
   The production compiler checks server components, static generation boundaries, and bundling rules more aggressively than development mode.
5. Local toolchain interference
   Custom shell environment variables, experimental Node flags, antivirus file locking, or monorepo-level config can affect a supposedly fresh app.

So the key insight is this: a clean scaffolded app failing on next build usually points to the runtime and install environment, not to the starter code itself.

Step-by-Step Solution

Follow these steps in order. They cover the most reliable path to fixing this issue.

1. Verify your Node.js version

Check your current runtime:

node -v

If you are on an older Node release, switch to a current supported version such as Node 18 LTS or Node 20 LTS, then recreate or reinstall the project. If you use nvm:

nvm install 20
nvm use 20
node -v

Then clean the project:

rm -rf node_modules package-lock.json .next
npm install
npm run build

2. Reinstall dependencies from a clean state

A broken initial install is one of the most common reasons a brand-new project fails.

rm -rf node_modules package-lock.json .next
npm cache clean --force
npm install
npm run build

If the app was created with npm, keep using npm. Avoid switching to pnpm or yarn unless you intentionally want to regenerate the lockfile.

3. Confirm the generated Next.js version

Make sure the installed package actually matches the expected release:

npm ls next react react-dom

You should see a consistent set of versions. If the tree looks invalid or duplicated, reinstall again after deleting the lockfile.

4. Test with a brand-new project in a clean directory

Create a separate sample app to verify whether the problem is global or project-specific:

npx create-next-app@latest next15-build-test
cd next15-build-test
npm run build

If this clean test works, then your original folder likely has environmental interference such as inherited config files, shell variables, or workspace-level settings.

5. Check for hidden workspace or monorepo config

If your project was created inside a larger repository, parent-level configuration may affect builds. Look for files such as:

• package.json with workspaces
• .npmrc
• .nvmrc
• tsconfig.json inheritance
• eslint shared config

Try creating the app outside the monorepo and build it there.

6. Inspect the exact build error output

If the build still fails, run the command again and focus on the first real error line rather than the final summary:

npm run build

Typical patterns include:

• Node/runtime syntax errors such as unsupported APIs
• Module resolution errors caused by incomplete installs
• React/Next version mismatch
• Permission or filesystem issues on Windows or locked directories

7. Pin to a stable Node LTS in the project

To prevent future mismatches, add an engine constraint in package.json:

{
  "engines": {
    "node": ">=18.18.0"
  }
}

If your team uses nvm, also add an .nvmrc file:

20

8. Last-resort recovery: regenerate the app

If the issue only affects one freshly generated project and all environment checks look correct, regenerate it completely:

cd ..
rm -rf your-project-name
npx create-next-app@latest your-project-name
cd your-project-name
npm run build

This helps when the initial scaffold was created during a bad package registry response or interrupted installation.

Common Edge Cases

Building on Windows with locked files

Windows security tools or editors can temporarily lock files inside .next or node_modules. Close running dev servers, terminate Node processes, then clean and reinstall.

taskkill /F /IM node.exe
rmdir /s /q .next
rmdir /s /q node_modules
npm install
npm run build

Creating the app behind a proxy or private registry

If your company uses a custom npm registry, some packages may install incorrectly or resolve to mirrored versions late. Verify your registry settings:

npm config get registry

If needed, compare with the official npm registry in a test environment.

Using canary or pre-release packages indirectly

A parent workspace or global tooling setup can accidentally influence version resolution. Always inspect the installed dependency graph with npm ls.

TypeScript or ESLint config inherited from parent directories

A clean Next app can fail if it automatically picks up stricter configs from a parent folder. Building the same app outside that directory usually confirms the cause.

Mismatch between local and CI environments

If the project builds locally but fails elsewhere, compare:

• Node.js version
• npm version
• lockfile contents
• environment variables

FAQ

Why does next dev work but next build fail?

Development mode and production build mode do not execute identical pipelines. The build step performs stricter analysis, route optimization, bundling, and environment validation, so hidden dependency or runtime issues often appear only during npm run build.

Do I need to downgrade Next.js 15.0.1 to fix this?

Usually no. This issue is more often caused by Node version mismatch or a bad dependency install than by the framework version itself. First test with a clean install on a supported Node LTS release.

What should I include when reporting the problem?

Include the exact output of node -v, npm -v, the full npm run build error log, and whether the issue reproduces in a brand-new app created in a separate directory. That information makes the root cause much easier to identify.

The fastest fix path is simple: upgrade to a supported Node.js LTS, delete node_modules, delete the lockfile, reinstall with the same package manager, and run npm run build again. For most fresh Next.js 15.0.1 projects, that resolves the build error immediately.