# 3D slicer for MAC cannot install slicer extensions from files

**URL:** <https://discourse.slicer.org/t/3d-slicer-for-mac-cannot-install-slicer-extensions-from-files/24972>\
**Category:** Support\
**Created:** [August 29, 2022, 7:56am UTC](https://discourse.slicer.org/t/3d-slicer-for-mac-cannot-install-slicer-extensions-from-files/24972 "2022-08-29T07:56:41Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![shai-ikko](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/shai-ikko/32/15765_2.png) [@shai-ikko](https://discourse.slicer.org/u/shai-ikko)\
**Post date:** [August 29, 2022, 7:56am UTC](https://discourse.slicer.org/t/3d-slicer-for-mac-cannot-install-slicer-extensions-from-files/24972/1 "2022-08-29T07:56:41Z")

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Hi,

I am developing a pure-python extension of Slicer. It is, at this point, private, so I cannot distribute it through the general extension server, and I have distributed it internally as a zip file. Most users are on Windows, and had no issues, but on a Mac the extension could not be installed.

This is not the issue of [3D slicer for MAC cannot install slicer extensions](https://discourse.slicer.org/t/3d-slicer-for-mac-cannot-install-slicer-extensions/2945) – extensions from the manager are installed with no problem; but when trying to install the Zip file, we get

```auto
ctk::copyDirRecursively: Failed to copy nonexistent directory "/Applications/Slicer.app/Contents/Extensions-30893/MyExtension/30893-macosx-amd64-MyExtension-git8bf4715-2022-08-22/Slicer.app/Contents/Extensions-30893/MyExtension"
Failed to copy directory /Applications/Slicer.app/Contents/Extensions-30893/MyExtension/30893-macosx-amd64-MyExtension-git8bf4715-2022-08-22/Slicer.app/Contents/Extensions-30893/MyExtension into directory /Applications/Slicer.app/Contents/Extensions-30893/MyExtension-XXXXXX

```

(30893 is the build number for Slicer 5.0.3, I’ve replaced my real extension name with “MyExtension” here)

I have constructed the zip file “manually” – its contents are

```auto
+ 30893-macosx-amd64-MyExtension-git8bf4715-2022-08-22
| + lib
  | + Slicer-5.0
    | + qt-scripted-modules
      | MyExtension.py
| + share
  | + Slicer-5.0
    | CMakeLists.txt
    | MyExtension.s4ext

```

What am I doing wrong?

---

<div class="post-metadata">

**Author:** ![shai-ikko](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/shai-ikko/32/15765_2.png) [@shai-ikko](https://discourse.slicer.org/u/shai-ikko)\
**Post date:** [August 29, 2022, 3:12pm UTC](https://discourse.slicer.org/t/3d-slicer-for-mac-cannot-install-slicer-extensions-from-files/24972/2 "2022-08-29T15:12:27Z")

</div>

… what I was doing wrong was to assume that, because the module code in Python is cross-platform, the packaging should be similar. The archive structure for a Mac extension is completely different, I see.