Windows10下安装GPU版XGBoost报错：无法复制xgboost\lib

Hey there, I’ve fought through the exact same frustrating error while installing GPU-enabled XGBoost on Windows 10 with Python 3.6.4—let me break down what’s going wrong and how to fix it.

Why That "can't copy 'xgboost\lib'" Error Happens #

The root issue is that after your CMake build finishes, the compiled xgboost.dll library ends up in the build/Release folder, but the Python setup script expects it to live in a xgboost/lib directory (which doesn’t get created automatically with your current steps).

Quick Fix: Manually Move the Library File #

If you want a fast solution without changing your original workflow:

1. Navigate back to your main xgboost root folder, then create the missing lib directory inside the nested xgboost folder:

   mkdir xgboost/lib
   

2. Go to the build/Release folder, copy the xgboost.dll file, and paste it into the new xgboost/lib directory you just made.
3. Head back to the python-package folder and re-run the install command:

   python setup.py install
   

This should resolve the copy error immediately.

Better Long-Term Fix: Tweak CMake to Output to the Right Path #

To avoid manual file copying entirely, adjust your CMake command to send the compiled library straight to the path the setup script expects:

1. When running your initial CMake command, add an extra flag to set the release output directory:

   cmake .. -G "Visual Studio 14 2015 Win64" -DUSE_CUDA=ON -DCMAKE_RUNTIME_OUTPUT_DIRECTORY_RELEASE=../xgboost/lib
   

2. Proceed with the build as before:

   cmake --build . --target xgboost --config Release
   

3. Now the xgboost.dll will be automatically placed in xgboost/lib, so running python setup.py install in the python-package folder will work without any missing file errors.

Extra Tips to Avoid Headaches #

• Always run the VS2015 x64 Native Tools Command Prompt as Administrator: Permission issues can sometimes prevent CMake from generating files in the correct locations.
• Double-check that CUDA 9.0 is properly added to your system PATH, and that Visual Studio 2015 has the full Visual C++ components installed (the default install sometimes skips these—go to Programs and Features > Modify Visual Studio 2015 to verify).
• If you hit weird build errors, clean your build directory and start fresh:

  cd build
  rmdir /s /q *
  

  Then re-run the CMake and build commands from scratch.

内容的提问来源于stack exchange，提问作者Mihai Chelaru