FileNotFoundError

FileNotFoundError is raised when trying to open or access a file or directory that doesn't exist. It's a subclass of OSError and has errno set to ENOENT.

Common causes

• File path is incorrect or has a typo
• File was moved, renamed, or deleted
• Using relative path from wrong working directory
• Missing file extension in the path
• Permission issue masquerading as file not found

How to fix it

• Use os.path.exists() or Path.exists() to check before opening
• Use absolute paths or Path(__file__).parent for reliable paths
• Use try/except FileNotFoundError for graceful handling
• Use pathlib.Path for cross-platform path handling
• Log the full path when errors occur for easier debugging

Example

# Error example
with open("data.csv") as f:
    content = f.read()
# FileNotFoundError: [Errno 2] No such file or directory: 'data.csv'

# Fix: check existence first
from pathlib import Path

file_path = Path("data.csv")
if file_path.exists():
    content = file_path.read_text()

# Fix: use try/except
try:
    with open("data.csv") as f:
        content = f.read()
except FileNotFoundError:
    print("File not found, using defaults")
    content = ""

# Fix: use path relative to script
script_dir = Path(__file__).parent
data_file = script_dir / "data.csv"