: The file may not have been created with PyInstaller at all. It could be a native C++ binary or packaged with a different tool like Nuitka or py2exe. Technical Analysis of the "Cookie"
Not every Python executable is made with PyInstaller. Tools like
an existing executable, or is this error happening while you are trying to a program you just built?
Always run these in a virtual environment or sandbox. Unpacking unknown executables can trigger malicious behavior.