# PyTorch Setup Error: [WinError 126] The specified module could not be found.


People generally use pytorch to build neural networks these days. Building them needs the CUDA + python + pytorch trio. Here are some installation details.

![Image source: Wikipedia](/img/Pytorch.zh-cn-20240813151919593.webp)

**Recommended installation tutorial**:

This post supplements the parts the videos after 2024 didn't emphasize.

The Chinese pdf in the video is more detailed than the official download instructions, so I recommend it.

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## Installing CUDA

### Version matching

Note: <font color="#ff0000">CUDA and pytorch versions correspond one-to-one</font>, it's not a matter of downloading the latest.

For example, as of July 26, 2024 — the latest CUDA version is 12.7, but pytorch has no matching version for it.

Version matching can be checked on the [pytorch official site](https://pytorch.org/get-started/previous-versions/).

### Downloading CUDA

After downloading from the CUDA official site, the first time you choose a download location.

At this point the download location is **temporary installer storage** — the folder is deleted after downloading.

![First location choice](/img/Pytorch.zh-cn-20240813150143605.webp)

The second custom install location is the real CUDA install location. If the second location is the same as the first, the files will be deleted.

![Second location choice](/img/Pytorch.zh-cn-20240813150252949.webp)

## Installing Pytorch

After installing according to the tutorial, running it in python gives the following error:

```
 [WinError 126] The specified module could not be found.
```

![You followed the tutorial exactly, but still get an error?](/img/Pytorch.zh-cn-20240813150731276.webp)

The real cause is that the WIN11 environment conflicts with Pytorch.
Many python-related component errors are the same issue.

The solution is to download [visual studio](https://visualstudio.microsoft.com/zh-hans/downloads/?cid=learn-navbar-download-cta)

and download `MSVC v143-VS 2022 C++x64/x86 生成工具(最新)` inside it.

> The English name is `MSVC v143 -VS 2022 C++ x64/x86 build tools (Latest)`

![Downloading components](/img/Pytorch.zh-cn-20240813151629739.webp)


## References

- [OSError: [WinError 126] The specified module could not be found]（ https://github.com/pytorch/pytorch/issues/131662 ）
- [LeNet study notes](https://blog.bdim.moe/zh/posts/2024-7-13/)


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> Author: [滑翔闪](https://github.com/hzp2333/hzp2333.github.io)  
> URL: https://blog.huaxiangshan.com/en/posts/pytorch/