ImportError: DLL load failed while importing _ctypes: The specified module could not be found.

[misunderstoodreamer]

Hello to all,

I have a desktop application created with PyQT5 library. In order to give the application, I need to take the exe. When pandas library imported, exe throws me error called "ImportError: DLL load failed while importing _ctypes: The specified module could not be found." If I don't use pandas lib, exe will be created successfully. I have already tried to reinstall Anaconda3 and I use venv. Also I have tried different interpretors. How will I handle the problem? Any help will be appreciated.

[bwoodsend]

Don't use anaconda with PyInstaller. This is exactly the kind of nonsense you should expect to happen when you do. Install a normal build of Python from https://python.org/downloads and install PyInstaller and your code in that.

[rokm]

Looks like the _ctypes extension failed to load due to a missing DLL; which is either libffi-7.dll, python3x.dll, or vcruntim140.dll. Check if these are collected into your frozen application.

[bersbersbers]

Hi,
I have exactly the same problem. Here's my stack trace (of what I call new.exe):

Traceback (most recent call last):
  File "C:\Users\ContainerAdministrator\scoop\persist\python311\Lib\site-packages\PyInstaller\hooks\rthooks\pyi_rth_mplconfig.py", line 45, in <module>
  File "C:\Users\ContainerAdministrator\scoop\persist\python311\Lib\site-packages\PyInstaller\hooks\rthooks\pyi_rth_mplconfig.py", line 31, in _pyi_rthook
  File "PyInstaller\loader\pyimod02_importers.py", line 391, in exec_module
  File "PyInstaller\fake-modules\_pyi_rth_utils\__init__.py", line 23, in <module>
  File "PyInstaller\loader\pyimod02_importers.py", line 391, in exec_module
  File "PyInstaller\fake-modules\_pyi_rth_utils\_win32.py", line 12, in <module>
  File "PyInstaller\loader\pyimod02_importers.py", line 391, in exec_module
  File "ctypes\__init__.py", line 8, in <module>
ImportError: DLL load failed while importing _ctypes: The specified module could not be found.

As you see, I build this executable on a private GitLab CI, using a mcr.microsoft.com/windows/server:ltsc2022 image into which I install scoop followed by python311. I am no (aware of) using Anaconda in any way.

Interestingly, I recently switched to this image and way of installing Python from using python:3.11 images, from which the executable (old.exe) would easily run, so I looked into the differences.

First, when I copy libffi-8.dll next to new.exe, it does run. This is not reuired in old.exe. Now,

Looks like the _ctypes extension failed to load due to a missing DLL; which is either libffi-7.dll, python3x.dll, or vcruntim140.dll. Check if these are collected into your frozen application.

I did. In fact, it seems to be libffi-8.dll now, but the interesting point is that old.exe has libffi-8.dll, libcrypto-3.dll, and libssl-3.dll in the MEI folder, while new.exe have the same files (plus tcl86.t.dll and tk86t.dll) in a dlls subfolder of the MEI folder. So libffi-8.dll is bundled with the application, but in a different location than in old.exe.

Is that a PyInstaller bug? Is that something I can easily fix? Or is scoop doing some magic that confuses PyInstaller? I should add that I test my application on the same CI before building it, and there, everything seems to run fine.

Here's a comparison of the MEI folders using windiff:

(pyprojec.toml and metadata differ since I relaxed a requirement on PySide6-Essentials, but since pyi_rth_mplconfig.py is related to matplotlib, I don't think this plays a role here. Also, I cannot reproduce the problem using the same build commands on the same scoop/python311 locally.)

[bersbersbers]

I should add that I can reproduce the problem locally now. The difference was in my use of a .venv as well:

• Install scoop, then scoop install python311, then pip install pyinstaller, etc.: fails
• Install scoop, then scoop install python311, then create and activate a .venv, then pip install pyinstaller, etc.: works!

[bersbersbers]

I filed #8023