cmake error for opencv 3.2 using vs2017

[CosmosHua]

System information (version)

• OpenCV => 3.2
• Operating System / Platform => Windows 10 64 Bit
• Compiler => Visual Studio 2017

Detailed description

CMake Error at F:/OpenCV/sources/cmake/OpenCVUtils.cmake:1043 (file):
file DOWNLOAD cannot open file for write.
Call Stack (most recent call first):
F:/OpenCV/opencv_contrib/modules/dnn/cmake/OpenCVFindLibProtobuf.cmake:32 (ocv_download)
F:/OpenCV/opencv_contrib/modules/dnn/CMakeLists.txt:5 (include)

CMake Error at F:/OpenCV/sources/cmake/OpenCVUtils.cmake:1047 (message):
Failed to download . Status=
Call Stack (most recent call first):
F:/OpenCV/opencv_contrib/modules/dnn/cmake/OpenCVFindLibProtobuf.cmake:32 (ocv_download)
F:/OpenCV/opencv_contrib/modules/dnn/CMakeLists.txt:5 (include)

Steps to reproduce

I used cmake-gui, after the second time press "Configure", there those errors. I don't know how to deal with.