# Extension manager error after linux build

**URL:** <https://discourse.slicer.org/t/extension-manager-error-after-linux-build/29744>\
**Category:** Development\
**Tags:** build, extensions-manager, linux\
**Created:** [May 31, 2023, 7:06am UTC](https://discourse.slicer.org/t/extension-manager-error-after-linux-build/29744 "2023-05-31T07:06:15Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Adama\_w](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/adama_w/32/15749_2.png) [@Adama\_w](https://discourse.slicer.org/u/Adama_w)\
**Post date:** [May 31, 2023, 7:06am UTC](https://discourse.slicer.org/t/extension-manager-error-after-linux-build/29744/1 "2023-05-31T07:06:15Z")

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Operating system: Linux Ubuntu 22.04.2 LTS 64-bit  
Slicer version: 5.0.2 & 5.2.1  
Expected behavior: Installed extension  
Actual behavior: Error message: Failed downloading: [https://slicer-packages.kitware.com/api/v1/file/63e348f3893957](https://slicer-packages.kitware.com/api/v1/file/63e348f3893957)

I successfully ran the builds and when I open the extension manager, the extensions display correctly (I looked into [this](https://github.com/Slicer/Slicer/issues/6577) solution but the issue is not the same as, in my case, the extension manager is not empty) but then when I click “install” for any extension, I get the error mentioned above.  
Also when I download the extension manually from the [extension catalog](https://extensions.slicer.org/catalog/All/30893/), the extension is removed every time I restart Slicer

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<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:** [May 31, 2023, 2:22pm UTC](https://discourse.slicer.org/t/extension-manager-error-after-linux-build/29744/2 "2023-05-31T14:22:35Z")

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If you build Slicer then you also need to build all the extensions you want to use. See more information [here](https://slicer.readthedocs.io/en/latest/developer_guide/build_instructions/overview.html#extensions-for-developer-builds-of-slicer).