The official release of OpenCV3. 4 .2 version only 64bit, due to the needs of the project and now it re-compiled x86 libraries. Download Source: Official github repository HTTPS: // github.com/opencv/opencv/releases, download OpenCV3.4.2 download, install CMake Official website: HTTPS: // cmake.org/download/ download the latest version, there is no difficulty Compile Open CMake Browse Source -> XXX/opencv/sources Browse Build -> XXX/opencv/build/x86 Configure, waiting to complete, not halfway off the network, takes about 50min. Click Configure option until no red box up Check BUILD_opencv_world, for generating opencv_world342.dll Click the Generate button to generate VS project, relatively fast 10 min ' within open solutions in XXX / opencv / build / find OpenCV.sln x86 directory, double-click operation Select Release and x86 Generating a direct build takes about 1H