# Use opencv\_traincascade

**URL:** <https://forum.opencv.org/t/use-opencv-traincascade/17587>\
**Category:** Python\
**Created:** [May 9, 2024, 12:19pm UTC](https://forum.opencv.org/t/use-opencv-traincascade/17587 "2024-05-09T12:19:52Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Lionel\_Bouck](https://avatars.discourse-cdn.com/v4/letter/l/51bf81/32.png) [@Lionel\_Bouck](https://forum.opencv.org/u/Lionel_Bouck)\
**Post date:** [May 9, 2024, 12:19pm UTC](https://forum.opencv.org/t/use-opencv-traincascade/17587/1 "2024-05-09T12:19:53Z")

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Hello,  
I want to train a haar cascade classifier. I need to use a command with `opencv_traincascade`. It doesn’t work with a recent version of open cv. There are posts where they say I need to switch to an older version. Which I did. I switched to the 3.4 version (I did a git clone of open cv and then git checkout 3.4). Then I tried to build opencv with cmake (I followed this [doc](https://docs.opencv.org/4.x/d5/de5/tutorial_py_setup_in_windows.html)). But I got errors. In the CMakeError file it says ucrtd.lib can’t be opened.