# Opening ALPACA for the first time and stuck on "Installing ALPACA Python Packages...."

**URL:** <https://discourse.slicer.org/t/opening-alpaca-for-the-first-time-and-stuck-on-installing-alpaca-python-packages/43415>\
**Category:** Support\
**Tags:** slicermorph, alpaca\
**Created:** [June 18, 2025, 7:13pm UTC](https://discourse.slicer.org/t/opening-alpaca-for-the-first-time-and-stuck-on-installing-alpaca-python-packages/43415 "2025-06-18T19:13:20Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![jsguerra](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@jsguerra](https://discourse.slicer.org/u/jsguerra)\
**Post date:** [June 18, 2025, 7:13pm UTC](https://discourse.slicer.org/t/opening-alpaca-for-the-first-time-and-stuck-on-installing-alpaca-python-packages/43415/1 "2025-06-18T19:13:20Z")

</div>

I recently upgraded my SSD and re-installed Slicermorph and the ALPACA extension. I went ahead and tried to open ALPACA for the first time since the new install and I seem to be stuck in the “Installing ALPACA Python Packages. This may take a minute..” pop-up for about 10 minutes (before writing this).

When I look at the Python console, the following output is in red letters:  
In the future `np.bool` will be defined as the corresponding NumPy scalar.  
Traceback (most recent call last):  
File “C:/Users/JSG/AppData/Local/slicer.org/Slicer 5.8.1/slicer.org/Extensions-33241/SlicerMorph/lib/Slicer-5.8/qt-scripted-modules/ALPACA.py”, line 126, in setup  
import itk  
File “C:\Users\JSG\AppData\Local\slicer.org\Slicer 5.8.1\lib\Python\Lib\site-packages\itk\__init_\_.py”, line 59, in   
from itk.support.extras import \*  
File “C:\Users\JSG\AppData\Local\slicer.org\Slicer 5.8.1\lib\Python\Lib\site-packages\itk\support\extras.py”, line 37, in   
import itk.support.types as itkt  
File “C:\Users\JSG\AppData\Local\slicer.org\Slicer 5.8.1\lib\Python\Lib\site-packages\itk\support\types.py”, line 178, in   
) = itkCType.initialize\_c\_types\_once()  
File “C:\Users\JSG\AppData\Local\slicer.org\Slicer 5.8.1\lib\Python\Lib\site-packages\itk\support\types.py”, line 143, in initialize\_c\_types\_once  
_B: “itkCType” = itkCType(“bool”, “B”, np.dtype(np.bool))  
File "C:\Users\JSG\AppData\Local\slicer.org\Slicer 5.8.1\lib\Python\Lib\site-packages\numpy\_init_.py", line 353, in **getattr**  
raise AttributeError( **former\_attrs** [attr])  
AttributeError: module ‘numpy’ has no attribute ‘bool’.  
`np.bool` was a deprecated alias for the builtin `bool`. To avoid this error in existing code, use `bool` by itself. Doing this will not modify any behavior and is safe. If you specifically wanted the numpy scalar type, use `np.bool_` here.  
The aliases was originally deprecated in NumPy 1.20; for more details and guidance see the original release note at:  
[NumPy 1.20.0 Release Notes — NumPy v2.4.dev0 Manual](https://numpy.org/devdocs/release/1.20.0-notes.html#deprecations)

Any help would be greatly appreciated!

---

<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:** [June 18, 2025, 7:46pm UTC](https://discourse.slicer.org/t/opening-alpaca-for-the-first-time-and-stuck-on-installing-alpaca-python-packages/43415/2 "2025-06-18T19:46:12Z")

</div>

Thanks for reporting. I can reproduce this in a fresh install. Opened an issue [ALPACA failing to install on 5.8.1 on windows due to ITK error · Issue #402 · SlicerMorph/SlicerMorph · GitHub](https://github.com/SlicerMorph/SlicerMorph/issues/402) you can track its update.

---

<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:** [June 19, 2025, 4:06pm UTC](https://discourse.slicer.org/t/opening-alpaca-for-the-first-time-and-stuck-on-installing-alpaca-python-packages/43415/3 "2025-06-19T16:06:56Z")

</div>

@jsguerra If you are tracking the github issue, until the fix is integrated, the workaround is to manually install the numpy. These steps worked for me:

1. in Python console type `pip\_install(“numpy==2.00”)’
2. Restart Slicer
3. Switch to ALPACA

It should continue installing remaining packages (pandas) and then ALPACA should be working.

---

<div class="post-metadata">

**Author:** ![jsguerra](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@jsguerra](https://discourse.slicer.org/u/jsguerra)\
**Post date:** [June 19, 2025, 4:37pm UTC](https://discourse.slicer.org/t/opening-alpaca-for-the-first-time-and-stuck-on-installing-alpaca-python-packages/43415/4 "2025-06-19T16:37:40Z")

</div>

@muratmaga Yes, I was literally just looking through the github issue! I’ll try your instructions, thank you!