# OpenIGTLinkIF module is not loaded

**URL:** <https://discourse.slicer.org/t/openigtlinkif-module-is-not-loaded/20441>\
**Category:** Support\
**Tags:** openigtlink, linux\
**Created:** [November 1, 2021, 5:32pm UTC](https://discourse.slicer.org/t/openigtlinkif-module-is-not-loaded/20441 "2021-11-01T17:32:23Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![lb123](https://avatars.discourse-cdn.com/v4/letter/l/85e7bf/32.png) [@lb123](https://discourse.slicer.org/u/lb123)\
**Post date:** [November 1, 2021, 5:32pm UTC](https://discourse.slicer.org/t/openigtlinkif-module-is-not-loaded/20441/1 "2021-11-01T17:32:23Z")

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Hi,

I built Slicer 4.13.0 in Ubuntu 20.04.3 LTS and then I installed the following extensions using the Extensions Manager:

 ![Untitled2](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/b/5/b59476f854d330b0ca6c1a207355e6c9c36ace0f.png)

After the installation, I restarted Slicer but I noticed that only some IGT modules are present, as you can see from the following screenshot:

 ![thumbnail_Image](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/f/8/f8b5516b83be2a343c6e8503b51c66faf0863975.jpeg)

Searching for OpenIGTLinkIF module I saw this message:

 ![Untitled](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/d/2/d23a2978d9a29f86e6bfb41eca5092dc945945f0.png)

Do you know what I should do to use OpenIGTLinkIF?

Thank you

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**Author:** ![Sunderlandkyl](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/sunderlandkyl/32/79987_2.png) [@Sunderlandkyl](https://discourse.slicer.org/u/Sunderlandkyl)\
**Post date:** [November 1, 2021, 6:10pm UTC](https://discourse.slicer.org/t/openigtlinkif-module-is-not-loaded/20441/2 "2021-11-01T18:10:31Z")

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If you have built Slicer, then you will need to build all of the extensions that you need as well. The extensions downloaded from the Extension Manager won’t be compatible.

Some more info here:

> [@Mac preview release build failed to load content in extension manager](https://discourse.slicer.org/t/mac-preview-release-build-failed-to-load-content-in-extension-manager/19899/2):
>
> This is the expected behavior. If you build Slicer then you also need to build all the extenions that you want to use to ensure ABI compatibility. After you have build Slicer on your computer (which is not very easy), building the extensions is trivial, just two CMake commands - see [here](https://slicer.readthedocs.io/en/latest/developer_guide/extensions.html#build-test-and-package).

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**Author:** ![lb123](https://avatars.discourse-cdn.com/v4/letter/l/85e7bf/32.png) [@lb123](https://discourse.slicer.org/u/lb123)\
**Post date:** [November 2, 2021, 11:22am UTC](https://discourse.slicer.org/t/openigtlinkif-module-is-not-loaded/20441/3 "2021-11-02T11:22:10Z")

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Thank you! I did like you said, but now I have an other strange issue [Multiple sessions of Slicer are launched in a loop - Support - 3D Slicer Community](https://discourse.slicer.org/t/multiple-sessions-of-slicer-are-launched-in-a-loop/20454)

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**Author:** ![SlicerIsGood](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/slicerisgood/32/16309_2.png) [@SlicerIsGood](https://discourse.slicer.org/u/SlicerIsGood)\
**Post date:** [August 16, 2022, 9:56am UTC](https://discourse.slicer.org/t/openigtlinkif-module-is-not-loaded/20441/4 "2022-08-16T09:56:26Z")

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but，if there are two modules are needed to be applied in customized Slicer app, how to build the two extensions?