SCP causes infinite QGIS window loop on macOS M4 with QGIS 3.44.6

[cesare710]

Description:
Environment

OS: macOS Sonoma 14.7.2 (Tahoe 26.2)
Hardware: MacBook M4 (ARM64)
QGIS: 3.44.6
Python: 3.12 (QGIS bundled)
SCP versions tested: 8.3.0, 8.5.0

Problem

When attempting to enable the Semi-Automatic Classification Plugin, QGIS enters an infinite loop that continuously opens new QGIS windows. The process cannot be stopped except by force quitting QGIS.
Steps to Reproduce

Install SCP via QGIS Plugin Manager or manually
Go to Plugins → Manage and Install Plugins → Installed
Check the box to enable "Semi-Automatic Classification Plugin"
Multiple QGIS windows start opening continuously

Dependencies Status

All dependencies are correctly installed and working:

✅ remotior_sensus - installed and importable
✅ scipy 1.16.3 - installed, ARM64 native
✅ matplotlib 3.10.8 - installed, ARM64 native
✅ All libraries verified as ARM64 compatible

Verified in QGIS Python Console:
python

import remotior_sensus # ✓ Works
import scipy # ✓ Works
import matplotlib # ✓ Works

## Error Messages
Console shows:

Sorgente Dati non Valida: /from multiprocessing.resource_tracker import main;main(27) non è una sorgente dati valida o riconosciuta.

This suggests the issue is related to multiprocessing during plugin initialization.
Additional Notes

The plugin installs successfully
The problem occurs specifically during the startPlugin() phase
Both versions 8.3.0 and 8.5.0 exhibit the same behavior
This appears to be a macOS-specific issue with multiprocessing in QGIS plugins

Is there a known workaround for macOS M-series chips, or is a fix planned for this issue?

[semiautomaticgit]

Hello @cesare710 , thank you for reporting this.

It seems an issue related to multiprocessing, but it could be caused by a partially failed installation of QGIS or interaction between other Python modules.
Please uninstall any other plugin and reinstall the SCP, and try again.

Is there a known workaround for macOS M-series chips, or is a fix planned for this issue?

Unfortunately I don't have any specific information for macOS M-series chips.

[cesare710]

Thanks, I unistalled all the plugins. This is the error I got:
Impossibile caricare il plugin 'SemiAutomaticClassificationPlugin' a causa di un errore chiamando il metodo classFactory()

ModuleNotFoundError: No module named 'scipy'
Traceback (most recent call last):
File "/Applications/QGIS.app/Contents/Frameworks/lib/python3.12/site-packages/qgis/utils.py", line 478, in _startPlugin
plugins[packageName] = package.classFactory(iface)
^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/Users/cesare/Library/Application Support/QGIS/QGIS3/profiles/default/python/plugins/SemiAutomaticClassificationPlugin/init.py", line 63, in classFactory
from .semiautomaticclassificationplugin import (
File "/Applications/QGIS.app/Contents/Frameworks/lib/python3.12/site-packages/qgis/utils.py", line 1100, in _import
mod = _builtin_import(name, globals, locals, fromlist, level)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/Users/cesare/Library/Application Support/QGIS/QGIS3/profiles/default/python/plugins/SemiAutomaticClassificationPlugin/semiautomaticclassificationplugin.py", line 48, in
from .core import config as cfg, util_qgis, util_qt, utils, util_gdal, messages
File "/Applications/QGIS.app/Contents/Frameworks/lib/python3.12/site-packages/qgis/utils.py", line 1100, in _import
mod = _builtin_import(name, globals, locals, fromlist, level)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/Users/cesare/Library/Application Support/QGIS/QGIS3/profiles/default/python/plugins/SemiAutomaticClassificationPlugin/core/utils.py", line 51, in
from scipy.spatial.distance import cdist
File "/Applications/QGIS.app/Contents/Frameworks/lib/python3.12/site-packages/qgis/utils.py", line 1100, in _import
mod = _builtin_import(name, globals, locals, fromlist, level)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
ModuleNotFoundError: No module named 'scipy'

Versione Python: 3.12.11 (main, Dec 18 2025, 07:47:48) [Clang 16.0.0 (clang-1600.0.26.6)]
Versione di QGIS: 3.44.6-Solothurn Solothurn, 386cd767

Percorso Python:
/Applications/QGIS.app/Contents/Resources/qgis/python
/Users/cesare/Library/Application Support/QGIS/QGIS3/profiles/default/python
/Users/cesare/Library/Application Support/QGIS/QGIS3/profiles/default/python/plugins
/Applications/QGIS.app/Contents/Resources/qgis/python/plugins
/Applications/QGIS.app/Contents/Frameworks/lib/python312.zip
/Applications/QGIS.app/Contents/Frameworks/lib/python3.12
/Applications/QGIS.app/Contents/Frameworks/lib/python3.12/lib-dynload
/Applications/QGIS.app/Contents/Frameworks/lib/python3.12/site-packages
/Users/cesare/Library/Application Support/QGIS/QGIS3/profiles/default/python

[semiautomaticgit]

You are welcome.

ModuleNotFoundError: No module named 'scipy'

You need to install the scipy dependency with the command
/Applications/QGIS.app/Contents/MacOS/bin/pip3 install scipy

[cesare710]

Thanks a lot.
I am experiencing a critical issue with SCP on MacOS Tahoe 26.2 using QGIS 3.44.6.
Issues:

1. At QGIS startup, multiple QGIS windows open automatically, causing a session conflict
2. The plugin fails to correctly locate the Python 3.12 environment on MacOS Tahoe. The standard /Contents/MacOS/bin/ path is not present in this QGIS version.
   Request:
   Could you please update the dependency loading script to support the new MacOS Tahoe directory structure? It seems the plugin struggles to verify remotior-sensus because it looks in hardcoded paths that have changed in recent QGIS/MacOS bundles.
   Environment:
   QGIS Version: 3.44.6
   OS: MacOS Tahoe 26.2
   Python 3.12
   SCP Version: 8.5
   Thank you for your great work on this plugin

[semiautomaticgit]

You are very welcome @cesare710 .

The plugin fails to correctly locate the Python 3.12 environment on MacOS Tahoe. The standard /Contents/MacOS/bin/ path is not present in this QGIS version.
Request:
Could you please update the dependency loading script to support the new MacOS Tahoe directory structure? It seems the plugin struggles to verify remotior-sensus because it looks in hardcoded paths that have changed in recent QGIS/MacOS bundles.

The plugin loads the Python libraries in the QGIS environment.
Unfortunately the environment is managed by QGIS, therefore I think you could ask for support at the QGIS community.

At QGIS startup, multiple QGIS windows open automatically, causing a session conflict

I think this is caused by the issues in the enviroment mentioned before, but I'll try to look into it.

[cesare710]

Thank you very much, Luca, for your interest in solving the problem of opening multiple QGIS windows. With the release of QGIS version 4 and SCP version 9 imminent, it is worth focusing attention on the next versions. It would be very helpful if the plugin could log specifically why a library fails to load; this would help users on new hardware like M4 chip to debug environment issues without crashing the entire QGIS session. Thank you for your hard work on the transition to QGIS 4 and for your commitment to improving the plugin's stability on macOS. Best regards, Cesare. Il giorno ven 9 gen 2026 alle ore 18:55 Luca Congedo < ***@***.***> ha scritto:

…

*semiautomaticgit* left a comment (semiautomaticgit/SemiAutomaticClassificationPlugin#432) <#432 (comment)> You are very welcome @cesare710 <https://github.com/cesare710> . The plugin fails to correctly locate the Python 3.12 environment on MacOS Tahoe. The standard /Contents/MacOS/bin/ path is not present in this QGIS version. Request: Could you please update the dependency loading script to support the new MacOS Tahoe directory structure? It seems the plugin struggles to verify remotior-sensus because it looks in hardcoded paths that have changed in recent QGIS/MacOS bundles. The plugin loads the Python libraries in the QGIS environment. Unfortunately the environment is managed by QGIS, therefore I think you could ask for support at the QGIS community. At QGIS startup, multiple QGIS windows open automatically, causing a session conflict I think this is caused by the issues in the enviroment mentioned before, but I'll try to look into it. — Reply to this email directly, view it on GitHub <#432 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/BNAFMSEDTCCMLONJZVJRVNL4F7TQNAVCNFSM6AAAAACQVBFSX6VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTOMRZHE3TQOBZGA> . You are receiving this because you were mentioned.Message ID: <semiautomaticgit/SemiAutomaticClassificationPlugin/issues/432/3729978890@ github.com>

[cesare710]

Hi Luca,
OS: macOS Sonoma 14.7.2 (Tahoe 26.2)
Hardware: MacBook M4 (ARM64).
I installed QGIS (3.40.3) and Remotior Sensus with Mamba (Python 3.12) and now SCP works regularly.
GDAL works regularly.
GRASS doesn't work; I am using the Grass program in applications for now separately from QGIS
(I can't find the option to insert the Grass path).
I installed successfully with Mamba also Whitebox Tools.
In the future I would like to use Mamba also for QGIS version 4 and new Remotior Sensus.
Thank you for your commendable work.

[semiautomaticgit]

You are very welcome @cesare710 . Thank you for your feedback