I have a situation very much like the one at Error “ImportError: DLL load failed: %1 is not a valid Win32 application”, but the answer there isn’t working for me.

My Python code says:

import cv2

But that line throws the error shown in the title of this question.

I have OpenCV installed in C:\lib\opencv on this 64-bit machine. I’m using 64-bit Python.

My PYTHONPATH variable: PYTHONPATH=C:\lib\opencv\build\python\2.7. This folder contains cv2.pyd and that’s all.

My PATH variable: Path=%OPENCV_DIR%\bin;... This folder contains 39 DLL files such as opencv_core246d.dll.

OPENCV_DIR has this value: OPENCV_DIR=C:\lib\opencv\build\x64\vc11.

The solution at Error “ImportError: DLL load failed: %1 is not a valid Win32 application” says to add “the new opencv binaries path (C:\opencv\build\bin\Release) to the Windows PATH environment variable”. But as shown above, I already have the OpenCV binaries folder (C:\lib\opencv\build\x64\vc11\bin) in my PATH. And my OpenCV installation doesn’t have any Release folders (except for an empty one under build/java).

What’s going wrong? Can I tell Python to verbosely trace the loading process? Exactly what DLL files is it looking for?

I noticed that, according to http://www.dependencywalker.com/, the cv2.pyd in C:\lib\opencv\build\python\2.7 is 32-bit, whereas the machine and the Python I’m running are 64-bit. Could that be the problem? And if so, where can I find a 64-bit version of cv2.pyd?

Please check if the Python version you are using is also 64 bit. If not then that could be the issue. You would be using a 32-bit Python version and would have installed a 64 bit binaries for the OpenCV library.

Wow, I found yet another case for this problem. None of the above worked. Eventually I used python’s ability to introspect what was being loaded. For Python 2.7, this means:

import imp

This turned up a completely unexpected “cv2.pyd” file in an Anaconda DLL directory that wasn’t touched by multiple uninstall/install attempts. Python was looking there first and not finding my good installation. I deleted that cv2.pyd file and tried imp.find_module(“cv2”) again and python immediately found the right file and cv2 started working.

So if none of the other solutions work for you, make sure you use Python introspection to see what file Python is trying to load.

In my case, I have 64-bit Python, and it was lxml that was the wrong version–I should have been using the x64 version of that as well. I solved this by downloading the 64-bit version of lxml here:



This was the simplest answer to a frustrating issue.

I just had this problem. It turns out it was just because I was using an 64-bit version of the OpenCV file. I tried the x86 and it worked.

I had the same problem. Here’s what I did:

  1. I downloaded the pywin32 wheel file from here, then

  2. I uninstalled the pywin32 module. To uninstall, execute the following command in a command prompt.

    pip uninstall pywin32

  3. Then, I reinstalled pywin32. To install it, open the command prompt in the same directory where the pywin32 wheel file lies. Then execute the following command.

    pip install <Name of the wheel file with extension>
    Wheel file will be like: piwin32-XXX-cpXX-none-win32.whl

It solves the problem for me.

I copied cv2.pyd file from /opencv/build/python/2.7/x86 folder instead of from /x64 folder to C:/Python27/Lib/site-packeges. I followed rest of the instructions provided here.

Added by someone else, not verified: I also copy file cv2.pyd to folder C:/Python27/Lib/site-packages/cv2. It works.

For me the problem was that I was using different versions of Python in the same Eclipse project. My setup was not consistent with the Project Properties and the Run Configuration Python versions.

In menu Project ? Properties ? PyDev, I had the Interpreter set to Python 2.7.11.

In Run Configurations ? Interpreter, I was using the Default Interpreter. Changing it to Python 2.7.11 fixed the problem.

If your build system (CMake in my case) copies the file from <name>.dll to <name>.pyd, you will get this error if the original file wasn’t actually a DLL file. In my case, building shared libraries got switched off, so the underlying file was actually a *.lib.

I discovered this error by loading the pyd file in Dependency Walker and finding that it wasn’t valid.

Update NumPy.

pip install numpy --upgrade

It works for me!

This one worked for me:

pip install -- pywin32==227

I faced the same issue when I uninstalled and reinstalled a different version of 2.7.x of Python on my system using a 32-bit Windows Installer. I got the same error on most of my import statements.

I uninstalled the newly installed Python, downloaded a 64-bit Windows installer, reinstalled Python again, and it worked.

So I had problems installing vtk under Windows (as I use Python 3.7, there isn’t any binary available so far. Just for older Python versions pip install vtk is not working)

I did wrote Python in my cmd:

Python 3.7.3 on win32

So I now know I have Python 3.7.3 running on a 32 bit.

I then downloaded the correct wheel at VTK?8.2.0?cp37?cp37m?win32.whl

Next I installed that wheel:

pip install VTK-8.2.0-cp37-cp37m-win32.whl

Then I tested it and it worked:

import vtk

I experienced the same problem while trying to write code concerning speech-to-text.

The solution was very simple. Uninstall the previous pywin32 using the pip method:

pip uninstall pywin32

The above will remove the existing one which is by default for 32 bit computers. And install it again using

pip install pywin32

This will install the one for the 64 bit computer which you are using.

I had a similar issue while trying to run uvicorn,
Creating a new virtual environment and reinstalling the python packages worked

You can install opencv from official or unofficial sites.

Refer to this question and this issue if you are using Anaconda.

It has a very simple solution.
After installing opencv

cv2.pyd from C:\opencv\build\python\2.7\ **x64** to C:\Python27\Lib\site-packages

instead of, place cv2.pyd from C:\opencv\build\python\2.7\ **x86** to C:\Python27\Lib\site-packages

I got this error when trying to import MySQLdb.

What worked for me was to uninstall Python and then reinstall it.

I got the error after installing npm (https://www.npmjs.com/get-npm). One thing it did was install Python even though I already had it.

First I copied cv2.pyd from /opencv/build/python/2.7/x86 to C:/Python27/Lib/site-packeges. The error was

“RuntimeError: module compiled against API version 9 but this version of numpy is 7”

Then I installed numpy-1.8.0-win32-superpack-python2.7.exe and OpenCV works fine.

>>> import cv2
>>> print cv2.__version__

  1. Please make sure that you have installed a Python 2.7.12 or below version. Otherwise you will definitely get this error.
  2. Make sure the Oracle client is 64 bit installed if the OS is 64 bit.
  3. Make sure the Microsoft Visual C++ compiler for Python 2.7 is 64 for bit for a 64 bit OS or 32 bit for 32 bit.

Note: If your OS is 64 bit, install all packages of 64 bit or if the OS is 32 bit, install the 32-bit package.

This has worked for me. I have tried different methods, but this was my best solution.

Open a command prompt and type the following;

pip install opencv-python

(Make sure your Internet connection is on.)

After that, try importing it again.

It could also be that your Anaconda version is 32 bit when it should be 64 bit.

Thanks – Anton Daneyko

In my PC I had another Python framework installed, to which PYTHONPATH was referring.
After deleting PYTHONPATH /modification the name of the PYTHONPATH, issue is resolved

I found the solution. Maybe you can try to use the cmd window rather than the Anaconda prompt window to start your first Scrapy test.