If you start any Python process on OS X 10.11 (10.11.0 or 10.11.1) El Capitan, and run the OS built-in tool 'codesign' to verify the process, you will receive an error saying "code object is not signed at all".

Here's an example:

  1. Open Terminal.app. Type "python". This will start a normal Python REPL console.
  2. Open another terminal window. Run "ps | grep python" to find the process id of the Python REPL process. Let's say it's 555.
  3. Run command "codesign -v 555". codesign will report "555: code object is not signed at all"

However, if you run the following commands, it seems the python executable is properly signed:

$ which python

$ codesign -dvv `which python`
Format=Mach-O universal (i386 x86_64)
CodeDirectory v=20100 size=226 flags=0x0(none) hashes=6+2 location=embedded
Signature size=4105
Authority=Software Signing
Authority=Apple Code Signing Certification Authority
Authority=Apple Root CA
Info.plist=not bound
TeamIdentifier=not set
Sealed Resources=none
Internal requirements count=1 size=68

If you use codesign to verify any Perl or Ruby process, they are all fine. Also, in Yosemite, every Python process can be correctly verified by codesign.

What happened?

  • Dunno. Same here on my El-Capitan. Apple stock python has this behaviour. But the python from homebrew checks out fine. Oct 26, 2015 at 19:20

1 Answer 1


The executable located at /usr/bin/python does little more than spawn the application /System/Library/Frameworks/Python.framework/Versions/2.7/Resources/Python.app. That application bundle doesn't have its own signature, but presumably it piggybacks on the signature of the parent binary.

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