# Cannot download extension from http://slicer.kitware.com or https://extensions.slicer.org

**URL:** <https://discourse.slicer.org/t/cannot-download-extension-from-http-slicer-kitware-com-or-https-extensions-slicer-org/19798>\
**Category:** Support\
**Created:** [September 22, 2021, 1:02am UTC](https://discourse.slicer.org/t/cannot-download-extension-from-http-slicer-kitware-com-or-https-extensions-slicer-org/19798 "2021-09-22T01:02:36Z")\
**Posts on this page:** 6\
**Page:** 1

<div class="post-metadata">

**Author:** ![Gao\_Zhenyu](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/gao_zhenyu/32/12494_2.png) [@Gao\_Zhenyu](https://discourse.slicer.org/u/Gao_Zhenyu)\
**Post date:** [September 22, 2021, 1:02am UTC](https://discourse.slicer.org/t/cannot-download-extension-from-http-slicer-kitware-com-or-https-extensions-slicer-org/19798/1 "2021-09-22T01:02:36Z")

</div>

I am working at a hospital environment. Since the hospital environment is internal, the 3d slicer cannot access to Internet. Therefore, 3D Slicer cannot download and consume extension immediately.

I try to download the externsion from [http://slicer.kitware.com](http://slicer.kitware.com) but this website was unused. Then I goto [@KitwareMedical/slicer-extensions-webapp](https://extensions.slicer.org/catalog/all/29738/win) and hit the similar issue. I cannot download it from those websites.

Please, help!

---

<div class="post-metadata">

**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [September 22, 2021, 1:04am UTC](https://discourse.slicer.org/t/cannot-download-extension-from-http-slicer-kitware-com-or-https-extensions-slicer-org/19798/2 "2021-09-22T01:04:54Z")

</div>

Slicer applications and all extensions are fully portable. You can download and install Slicer and extensions on any computer that has internet access, then copy the entire installation folder to another computer and everything will work.

Alternatively, you can use the new extension download site as described [here](https://slicer.readthedocs.io/en/latest/user_guide/extensions_manager.html#download-extension-packages).

---

<div class="post-metadata">

**Author:** ![Gao\_Zhenyu](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/gao_zhenyu/32/12494_2.png) [@Gao\_Zhenyu](https://discourse.slicer.org/u/Gao_Zhenyu)\
**Post date:** [September 22, 2021, 1:10am UTC](https://discourse.slicer.org/t/cannot-download-extension-from-http-slicer-kitware-com-or-https-extensions-slicer-org/19798/3 "2021-09-22T01:10:12Z")

</div>

Thanks for the reply ! but my workmate told me he had try to copy the entire installation folder to other machine, but it doesn’t work.

You had memtion about [Extensions Manager — 3D Slicer documentation](https://slicer.readthedocs.io/en/latest/user_guide/extensions_manager.html#download-extension-packages) . I had found it a few days ago and it says I can download extension in [@KitwareMedical/slicer-extensions-webapp](https://extensions.slicer.org/catalog/All/30117/win) . But I cannot download it with chrome. (click download button did not trigger downloading)

---

<div class="post-metadata">

**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [September 22, 2021, 1:13am UTC](https://discourse.slicer.org/t/cannot-download-extension-from-http-slicer-kitware-com-or-https-extensions-slicer-org/19798/4 "2021-09-22T01:13:20Z")

</div>

> [@Gao\_Zhenyu](#):
>
> but my workmate told me he had try to copy the entire installation folder to other machine, but it doesn’t work

It works. You may need to use a recent Slicer Preview Release. If you have any problems then describe what you did, what you expected to happen, and what happened instead.

> [@Gao\_Zhenyu](#):
>
> But I cannot download it with chrome. (click download button did not trigger downloading)

This is a known issue, you can track the progress of fixing the problem [here](https://github.com/Slicer/Slicer/issues/5863). You can use the new extension download site as described [here](https://slicer.readthedocs.io/en/latest/user_guide/extensions_manager.html#download-extension-packages).

---

<div class="post-metadata">

**Author:** ![Gao\_Zhenyu](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/gao_zhenyu/32/12494_2.png) [@Gao\_Zhenyu](https://discourse.slicer.org/u/Gao_Zhenyu)\
**Post date:** [September 22, 2021, 1:21am UTC](https://discourse.slicer.org/t/cannot-download-extension-from-http-slicer-kitware-com-or-https-extensions-slicer-org/19798/5 "2021-09-22T01:21:03Z")

</div>

Thanks a lot! We will try again.

---

<div class="post-metadata">

**Author:** ![muratmaga](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/muratmaga/32/3622_2.png) [@muratmaga](https://discourse.slicer.org/u/muratmaga)\
**Post date:** [September 22, 2021, 10:51pm UTC](https://discourse.slicer.org/t/cannot-download-extension-from-http-slicer-kitware-com-or-https-extensions-slicer-org/19798/6 "2021-09-22T22:51:49Z")

</div>

We are in a hospital environment and encountered issues installing extensions. Working with IT security, it turned out a problem with the corporate firewall (this is explained by IT to me. Review of the traffic to [slicer-packages.kitware.com](http://slicer-packages.kitware.com) indicated that it was hitting the SSL inspection of the traffic. The site appears to be breaking due to the SSL inspection). They ended up implementing a SSL inspection bypass, which fixed the problem for us.

This may not be your issue, but at some point you may need to get your IT team involved.