FileNotFoundError: [Errno 2] No such file or directory — how to fix

Traceback (most recent call last):
  File "/home/me/project/src/app.py", line 1, in <module>
    with open("data.csv") as f:
FileNotFoundError: [Errno 2] No such file or directory: 'data.csv'

Quick fix: Build paths relative to the script: from pathlib import Path; path = Path(__file__).parent / "data.csv". Print os.getcwd() to see where Python is looking. On Windows, use raw strings r"C:\path" or forward slashes.

What it means

open("data.csv") looks for data.csv in the current working directory — the folder you ran python from, or the folder your IDE uses — not the folder that contains your script.

Check:

import os
print(os.getcwd())
print(os.listdir())

Fix 1: make paths relative to the script

from pathlib import Path

HERE = Path(__file__).resolve().parent
with open(HERE / "data.csv") as f:
    ...

Now it works no matter where you run it from. For a file one level up: HERE.parent / "data" / "data.csv".

Fix 2: run from the right folder / configure your IDE

• VS Code runs files with the workspace root as working directory. Set "python.terminal.executeInFileDir": true or adjust cwd in launch.json.
• PyCharm: Run configuration → Working directory.
• Jupyter uses the notebook's folder.
• cron/systemd jobs start in / or your home folder; always use absolute paths there.

Fix 3: Windows paths

Backslashes are escape characters in normal strings: "C:\new\data.csv" contains a newline (\n).

open(r"C:\new\data.csv")       # raw string
open("C:/new/data.csv")        # forward slashes work too

Also check for hidden extensions: Explorer may show data.csv while the file is really data.csv.txt.

Fix 4: the directory doesn't exist when writing

open("out/result.txt", "w") fails if out/ doesn't exist. Create it first:

Path("out").mkdir(parents=True, exist_ok=True)

Fix 5: it's a program, not a file

FileNotFoundError from subprocess.run(["node", ...]) means the executable wasn't found on PATH. Use the full path, or shutil.which("node") to check.

Docker

Inside a container, the file must be copied in (COPY data.csv /app/) or mounted with -v. Paths from your host don't exist in the container.

Last updated 2026-10-29.