npm ERR! code EMFILE

npm opened too many files at once.

Frequently documented in developer and vendor support forums.

• Low system limit
• Large project
• Many dependencies

1. Increase ulimit on Unix
2. Close other applications
3. Restart system

Last reviewed: March 2026 How we review solutions

EMFILE stands for "Error Max FILES" and occurs when npm tries to open a file but the operating system has reached its per-process limit for open file descriptors. Every file, socket, and pipe that a process opens consumes a file descriptor, and the OS enforces a ceiling to prevent a single process from exhausting system resources. On macOS, the default soft limit is notoriously low at 256 open files, while Linux typically allows 1024. Modern npm projects with hundreds or thousands of packages in node_modules easily exceed these limits during installation, as npm opens many package.json files, tarballs, and temporary files simultaneously. The error is particularly common during npm install on large projects, especially the first install where everything must be extracted from cached tarballs. Development tools that watch file systems (Webpack dev server, Vite, Jest in watch mode, nodemon) also consume file descriptors for every watched file, and running these alongside npm install compounds the problem. The fix is straightforward: increase the file descriptor limit using ulimit (temporary) or by editing system configuration files (permanent).

1. Check the current limit: ulimit -n
2. Temporarily increase: ulimit -n 65536 (in the current shell)
3. Close other applications that may have many files open
4. On macOS, check the system limit: launchctl limit maxfiles
5. If using a file watcher, exclude node_modules from watching

Docker container with low default limits

Docker containers inherit file descriptor limits from the host or use their own defaults. Alpine-based containers often have a limit of 1024. Add --ulimit nofile=65536:65536 to your docker run command or set it in docker-compose.yml.

macOS Catalina and later reset limits on reboot

macOS resets ulimit values on each reboot despite edits to .bashrc or .zshrc. You need a LaunchDaemon plist to persist the change. Create /Library/LaunchDaemons/limit.maxfiles.plist with the desired limit.

File watcher leak in development

Tools like Webpack, Vite, and nodemon keep file descriptors open for every watched file. If you restart the dev server repeatedly without closing the old process, orphaned watchers accumulate. Kill stale Node processes: pkill -f node before restarting.

How to increase limit?

Run ulimit -n 65535 before npm install.

Is this a Windows issue?

More common on Unix systems.

What is a file descriptor?

A file descriptor is a handle the operating system assigns to every open file, network socket, or pipe. Each process has a limited number of these handles. When the limit is reached, any new open() call fails with EMFILE.

Why does macOS have such a low default limit?

macOS defaults to 256 open files per process for historical compatibility. This was sufficient for most applications decades ago but is far too low for modern Node.js development. Increasing it to 65536 has no negative side effects.

Does npm have a built-in way to handle EMFILE?

npm uses the graceful-fs library internally, which queues file operations when the limit is reached. However, extremely low limits (256) can still overwhelm the queue. Increasing the OS limit is the reliable fix.

• npm install – Official npm Docs
• package.json Reference – npm Docs