OSError: [WinError 193] %1 is not a valid Win32 application

# OSError: [WinError 193] %1 is not a valid Win32 application

The Python "OSError: [WinError 193] %1 is not a valid Win32 application" occurs when you try to run a script but forget to specify the executable file.

To solve the error, specify the executable file, e.g. python.exe.

Here is an example of how the error occurs.

Suppose we have the following example.py file.

example.py

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print('bobbyhadz.com')

for i in range(3):
    print(f'bobbyhadz.com {i}')

And we want to run the Python script from another script named main.py.

main.py

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import subprocess

# ⛔️ OSError: [WinError 193] %1 is not a valid Win32 application
subprocess.call(['example.py'])

os error win error 193 is not valid win32 application

The error is raised because we forgot to specify the executable as the first list item.

If you're trying to run a Python script from another Python script, you should use python.exe as the executable.

main.py

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import subprocess

# ✅ Works
subprocess.call(['python.exe', 'example.py'])

set python exe as executable

On Windows, you might also have to set py.exe as the executable.

main.py

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import subprocess

# ✅ Works
subprocess.call(['py.exe', 'example.py'])

py is a Windows alias for python.

The examples use the subprocess.call() method, however, the same can be achieved using subprocess.Popen().

main.py

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import subprocess

# ✅ Works
subprocess.Popen(['python.exe', 'example.py'])

If you don't have python in your PATH environment variable, try using sys.executable instead.

main.py

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import subprocess

# ✅ Works
subprocess.Popen([sys.executable, 'example.py'])

The sys.executable attribute is a string that returns the absolute path to the executable binary of the Python interpreter.

# Setting `shell` to `True` to solve the error

You can also try to set the shell argument to True in the call to subprocess.call() to solve the error.

main.py

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import subprocess

subprocess.call(['example.py'], shell=True)

If the shell argument is set to True, the specified command is executed through the shell.

When the argument is set to True, subprocess spawns an intermediate shell process and runs the command.

By default, the shell argument is set to False, so the command is run directly.

# Running a shell script from a Python script on Windows

If you are trying to run a .cmd file from a Python script on Windows, use the following code sample.

main.py

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import subprocess

subprocess.call(['example.cmd'], shell=True)

The code sample assumes that you have an example.cmd file located in the same directory as your main.py file.

example.cmd

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echo bobbyhadz.com

run cmd shell script from python script

# Additional Resources

You can learn more about the related topics by checking out the following tutorials:

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OSError: [WinError 193] %1 is not a valid Win32 application