# Opencv\_world451.dll missing in x86 build

**URL:** <https://forum.opencv.org/t/opencv-world451-dll-missing-in-x86-build/687>\
**Category:** Uncategorized\
**Created:** [January 6, 2021, 2:09am UTC](https://forum.opencv.org/t/opencv-world451-dll-missing-in-x86-build/687 "2021-01-06T02:09:04Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Eugene](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.opencv.org/eugene/32/445_2.png) [@Eugene](https://forum.opencv.org/u/Eugene)\
**Post date:** [January 6, 2021, 2:09am UTC](https://forum.opencv.org/t/opencv-world451-dll-missing-in-x86-build/687/1 "2021-01-06T02:09:04Z")

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Hello,  
I’m upgrading my Visual Studio v15 C++ project from openCV v3.4.3 to v4.5.1 in x86 configuration. I built it in CMake and then ran BUILD and INSTALL in OpenCV.sln in the Visual Studio. But I cannot find the opencv\_world451.dll anywhere. It’s supposed to be in …\install\x86\vc15\bin but it’s just not there. There are bunch of other dll files, but not the opencv\_world451.dll. Could anyone help?

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**Author:** ![Ceopee](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.opencv.org/ceopee/32/531_2.png) [@Ceopee](https://forum.opencv.org/u/Ceopee)\
**Post date:** [January 6, 2021, 6:23am UTC](https://forum.opencv.org/t/opencv-world451-dll-missing-in-x86-build/687/2 "2021-01-06T06:23:33Z")

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Hi Eugene,  
Maybe you forgot to check BUILD\_opencv\_world entry in the cmake file. By default its unchecked. It’s under the BUILD group, if you enable the grouped view on cmake GUI. You should tick the checkbox to produce opencv\_worldxxx.dll.

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**Author:** ![crackwitz](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.opencv.org/crackwitz/32/14_2.png) [@crackwitz](https://forum.opencv.org/u/crackwitz)\
**Post date:** [January 6, 2021, 7:27am UTC](https://forum.opencv.org/t/opencv-world451-dll-missing-in-x86-build/687/3 "2021-01-06T07:27:13Z")

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related

> <https://stackoverflow.com/questions/65589278/opencv-world451-dll-missing-in-opencv-4-5-1-x86-build>