NotADirectoryError: [Errno 20] Not a directory (Fix)

NotADirectoryError: [Errno 20] Not a directory happens when Python expects a folder path, but your code gives it a file path instead.

This usually appears with functions like os.listdir(), os.chdir(), and os.scandir(). These functions work with directories, not files.

Quick fix #

Use os.path.isdir() before calling a function that expects a directory:

import os

path = "notes.txt"

if os.path.isdir(path):
    print(os.listdir(path))
else:
    print("This path is not a directory:", path)

What this does:

Checks whether path is a directory
Only calls os.listdir() if the path is a folder
Avoids the error when the path points to a file

If you need help understanding path types, see working with file paths in Python.

What this error means #

This error means:

Python expected a directory path
You gave a file path or another non-directory path instead
A function like os.listdir() or os.chdir() cannot continue

In simple terms:

"documents/" is usually a directory path
"notes.txt" is usually a file path

If a function needs a folder, passing "notes.txt" will cause this error.

Why it happens #

Common reasons include:

A filename is passed to a function that needs a folder
Part of the path points to a file, not a directory
A variable name suggests a folder, but actually stores a file path
The path was built incorrectly

This is especially common when:

You are joining paths by hand
You are using user input
You assume a path is a folder without checking it first

Example that causes the error #

Suppose notes.txt is a real file in your current folder.

import os

print(os.listdir("notes.txt"))

Output:

Traceback (most recent call last):
  ...
NotADirectoryError: [Errno 20] Not a directory: 'notes.txt'

Read this bottom-up: os.listdir() needs a folder, but ’notes.txt’ is a file.

Why this fails #

os.listdir() lists the contents of a directory.

It can do this:

import os

print(os.listdir("documents"))

But it cannot do this:

import os

print(os.listdir("notes.txt"))

Because notes.txt is a file, not a folder.

If you want to learn more about this function, see os.listdir() explained.

How to fix it #

There are several ways to fix this error.

Pass the correct folder path #

If you meant to list a folder, pass the folder path:

import os

folder_path = "documents"
print(os.listdir(folder_path))

Check the path before using it #

import os

path = "notes.txt"

if os.path.isdir(path):
    print(os.listdir(path))
else:
    print("Expected a directory, but got:", path)

This is one of the safest beginner-friendly fixes.

You can also use os.path.exists() explained to check whether the path exists at all.

Use `open()` for files and `os.listdir()` for folders #

If your path is a file, use open() instead of os.listdir():

path = "notes.txt"

with open(path, "r") as file:
    content = file.read()

print(content)

Use:

open() for files
os.listdir() for folders

If needed, read more about the Python open() function.

Print the path value #

A very common problem is that the variable contains something different from what you expected.

import os

path = "notes.txt"
print("Path value:", path)

if os.path.isdir(path):
    print(os.listdir(path))
else:
    print("Not a directory")

Printing the path often helps you spot:

wrong filenames
missing folder names
incorrect path building
unexpected user input

File path vs directory path #

Understanding this difference helps prevent the error.

File path #

A file path points to one file:

"data.txt"
"images/photo.jpg"

You usually use file paths with functions like:

open()
os.path.isfile()

Directory path #

A directory path points to a folder:

"documents"
"images"
"projects/python"

You usually use directory paths with functions like:

os.listdir()
os.chdir()
os.scandir()

Different Python functions expect different path types. If you mix them up, errors happen.

Beginner debugging steps #

If you get this error, check these things in order.

1. Print the path #

print(path)

Make sure the value is really what you think it is.

2. Check whether the path exists #

import os

print(os.path.exists(path))

If it returns False, the path is wrong or missing.

3. Check whether it is a file or directory #

import os

print(os.path.isfile(path))
print(os.path.isdir(path))

This tells you what the path actually points to.

4. Check your current working directory #

Sometimes the path is relative, and Python is looking in a different place than you expect.

import os

print(os.getcwd())

5. Make sure you are using the right function #

If the path is a file, use open()
If the path is a folder, use os.listdir() or another directory function

If you need a full overview of these tools, see the Python os module overview.

Common places this appears #

You will often see this error in code like:

os.listdir(path)
os.chdir(path)
os.scandir(path)
Any code that expects a folder but receives a file path

For example, this will also fail if report.txt is a file:

import os

os.chdir("report.txt")

And this can fail when part of the path is a file:

import os

path = "notes.txt/archive"
print(os.listdir(path))

If notes.txt is a file, Python cannot treat it like a folder containing archive.

Common mistakes #

Common causes of NotADirectoryError include:

Calling os.listdir() on a file
Calling os.chdir() with a filename
Joining paths incorrectly
Confusing a file path variable with a folder path variable
Using user input without checking whether it is a directory

Useful debugging commands:

print(path)

import os
print(os.path.exists(path))
print(os.path.isfile(path))
print(os.path.isdir(path))
print(os.getcwd())

FAQ #

What is the difference between NotADirectoryError and FileNotFoundError? #

NotADirectoryError means the path exists, but it is not a folder.

FileNotFoundError means the path does not exist.

For that related case, see FileNotFoundError: [Errno 2] No such file or directory.

Can a file path cause NotADirectoryError? #

Yes. If a function expects a directory and you pass a file path, Python raises this error.

How do I check if a path is a directory? #

Use os.path.isdir(path).

Example:

import os

path = "documents"
print(os.path.isdir(path))

It returns:

True if the path is a directory
False otherwise

Should I use open() or os.listdir()? #