PermissionError
Python Programming Language
Severity: ModerateWhat Does This Error Mean?
A PermissionError means your Python program tried to access a file, folder, or system resource but the operating system denied it. Every file on your computer has permissions that control who can read, write, or execute it. If your Python script does not have the necessary permission, you get this error.
Affected Models
- Python 3.x
- Windows, macOS, and Linux
Common Causes
- Trying to write to a file or folder that is read-only or protected by the operating system
- Trying to access a file that another program (like Excel or Word) currently has locked open
- Running Python without administrator or root privileges when the operation requires them
- Trying to write to a system directory like C:\Windows or /etc without elevated permissions
- Attempting to delete or modify a file that belongs to another user account
How to Fix It
-
Check if another program has the file open. If you are trying to write to a CSV or Excel file, close it in Excel or any other application first.
Windows locks files when they are open in another program. The lock is released when you close the other program.
-
Check the file's permissions in your file explorer. Right-click the file, go to Properties, and look at the Security or Permissions tab to see who can read and write it.
If it is marked read-only, uncheck that option.
-
If your script needs to write to a protected folder (like Program Files), try writing to a less restricted location instead — like the user's Documents folder or a temp folder.
Use os.path.expanduser('~/Documents/output.txt') to get the path to the current user's Documents folder.
-
On Windows, try running your Python script as Administrator. Right-click your terminal or IDE and choose 'Run as administrator'.
Only do this when necessary — it is better to fix permissions on individual files than to always run as admin.
-
On macOS or Linux, you can change file permissions with chmod in the terminal. Example: 'chmod 644 myfile.txt' gives the owner read-write access.
Be careful with chmod — only change permissions on files you own and understand.
When to Call a Professional
PermissionErrors are usually fixable yourself by adjusting file permissions or running Python with the right privileges. Be careful when changing permissions on system files — only do so if you know what you are doing. If the error is on a file belonging to another user or application, consider a different approach rather than changing permissions.
Frequently Asked Questions
Why do I get PermissionError on my own files?
Even files you own can have restrictive permissions set. Also, if another program has the file open, your script may be denied access. Check if the file is open elsewhere, and check the file's permission settings in your file explorer.
Is it safe to run Python as Administrator to fix this?
It can fix the error, but running everything as Administrator is not a good habit. Administrator mode means a mistake in your code could accidentally damage system files. The safer approach is to fix the permissions on the specific file, or write to a folder you already have access to.
Why does PermissionError happen on Windows more than Mac or Linux?
Windows has stricter file locking — it locks files while they are open in another application. Mac and Linux are more permissive about concurrent file access. Windows also has User Account Control (UAC) which restricts access to system areas. Always close files in other applications before your script tries to write to them.