Common Installation Errors

On Windows

<XP>/Resources/plugins/XPPython3/win_x64/XPPython3.xpl: Error Code = 126 :
The specified module could not be found.
Cause:

X-Plane cannot load all DLLs required by plugin. In this case, the XPPython plugin is looking for Python DLL. The Python version of XPPython3 (3.6, 3.7, …, 3.10) looks for the same named DLL (python36.dll, python37.dll, …, pthon310.dll).

Solution:

Windows using your %PATH% environment variable to find DLLs, so when you install:

  • Add Python to environment variables.

If you forgot on the initial install of python, you can go to Windows Settings -> Apps -> Python 3.x (64-bit), select Modify, then go through the options until you find Add Python to environment variables.

You may want to restart your computer after python installation.

../_images/add_python_to_path.jpg

On Mac

You get popup on initial execution:

../_images/quarantine.png
Cause

The XPPython3 plugin developer (me) cannot be verified, because I’ve not paid Apple $100 / year to get a signature 1. So Apple decides that since it doesn’t know who I am, it cannot check the contents of the plugin, and will therefore not allow it to run without additional action on your part:

Solution

  1. Press Cancel. If you move it to the trash, you’ll have to download it again…

  2. Follow instructions to remove the quarantine as described in Mac Quarantine.

You get an eror message in a Log file complaining about SSL CERTIFICATES:

Failed with urllib: <urlopen error [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify
failed: self signed certificate in certificate chain (_ssl.c:1122)>

-or-

!!!! Installation Incomplete: Run /Applications/Python<version>/Install Certificates,
and restart X-Plane.
Cause:
../_images/install_python_mac.png

When installing python3 on Mac, there is an additional step you must do. It is documented by the python installation tool, but you (and I) didn’t actually read everything in the python installer.

See the highlighted section from the Mac python installer:

Solution:

Browse /Applications/Python<version> and read the ReadMe.rtf file you find there. This is the “Certificate verification and OpenSSL” issue mention in the ReadMe. Just double click on the Install Certificates command file and that will fix it.

../_images/installer_command_execution.png ../_images/mac_certificate_installer.png

On All Platforms

Can't open <folder> to scan for plugins.
Cause:

XPPython3 looks for its main plugin folder PythonPlugins (See Plugin Installation), and if not found, it will complain. Additionally, XPPython3 will look for aircraft-specific plugins specific to the loaded user aircraft (Global, Aircraft, and Scenery Plugins).

Solution:

If you were expecting python plugin to be loaded, check to make sure the file(s) are place in the correct location. If you’re not anticipating a plugin to be loaded, ignore the message.

1

“Apple signature costs $100/year”. I’m in favor of the quarantine system, but not crazy about having to pay to get a signature as I make no money on XPPython3. If you’d like to donate, I promise to use the first $100 of XPPython3 donations each year to purchase a signature so that others may avoid this hassle. You can donate through Paypal.