# Moose Extension was ERROR

**URL:** <https://discourse.slicer.org/t/moose-extension-was-error/44998>\
**Category:** Feature requests\
**Tags:** segmentation, extensions-manager\
**Created:** [November 8, 2025, 4:51am UTC](https://discourse.slicer.org/t/moose-extension-was-error/44998 "2025-11-08T04:51:05Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![akmal871026](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/akmal871026/32/11642_2.png) [@akmal871026](https://discourse.slicer.org/u/akmal871026)\
**Post date:** [November 8, 2025, 4:51am UTC](https://discourse.slicer.org/t/moose-extension-was-error/44998/1 "2025-11-08T04:51:05Z")

</div>

Dear All,

I am faced problem since install dependencies for Moose Extension.

Traceback (most recent call last):

File “D:\Slicer 5.8.1\bin\Python\slicer\util.py”, line 3303, in tryWithErrorDisplay

yield

File “D:/Slicer 5.8.1/slicer.org/Extensions-33241/SlicerMOOSE/lib/Slicer-5.8/qt-scripted-modules/MOOSE.py”, line 150, in button\_install\_dependencies\_clicked

self.dependency\_manager.install\_all\_dependencies()

File “D:/Slicer 5.8.1/slicer.org/Extensions-33241/SlicerMOOSE/lib/Slicer-5.8/qt-scripted-modules/MOOSE.py”, line 98, in install\_all\_dependencies

self.install\_moosez()

File “D:/Slicer 5.8.1/slicer.org/Extensions-33241/SlicerMOOSE/lib/Slicer-5.8/qt-scripted-modules/MOOSE.py”, line 60, in install\_moosez

slicer.util.pip\_install(“moosez\>=3.1.1”)

File “D:\Slicer 5.8.1\bin\Python\slicer\util.py”, line 3942, in pip\_install

\_executePythonModule(“pip”, args)

File “D:\Slicer 5.8.1\bin\Python\slicer\util.py”, line 3896, in \_executePythonModule

logProcessOutput(proc)

File “D:\Slicer 5.8.1\bin\Python\slicer\util.py”, line 3862, in logProcessOutput

raise CalledProcessError(retcode, proc.args, output=proc.stdout, stderr=proc.stderr)

subprocess.CalledProcessError: Command ‘[‘D:/Slicer 5.8.1/bin/../bin\\PythonSlicer.EXE’, ‘-m’, ‘pip’, ‘install’, ‘moosez\>=3.1.1’]’ returned non-zero exit status 1.

 ![Screenshot 2025-11-08 125011](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/2/a/2a2333f9b89e0d0982d9a1cbd9844fc629d90f65.png)

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<div class="post-metadata">

**Author:** ![jamesobutler](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/jamesobutler/32/7511_2.png) [@jamesobutler](https://discourse.slicer.org/u/jamesobutler)\
**Post date:** [November 8, 2025, 5:00am UTC](https://discourse.slicer.org/t/moose-extension-was-error/44998/2 "2025-11-08T05:00:21Z")

</div>

> [@akmal871026](#):
>
> slicer.util.pip\_install(“moosez\>=3.1.1”)

I believe the developers updated their extension to use a newer version of moosez that is technically Python 3.10 or newer compatible. Therefore it is likely the extension is no longer compatible with Slicer 5.8 which uses Python 3.9. Instead try latest Slicer Preview (soon to be Slicer 5.10 stable) as it uses Python 3.12.