[QGIS-Developer] Building QGIS with QT6 on Ubuntu: Python error at start

[pathmapper]

Hi,

I don't know what's wrong, but when I had similar problems, switching to 
Python 3.12 solved them for me.

Cheers,
Björn

On 21.07.2025 16:58, Alessandro Pasotti via QGIS-Developer wrote:
> Hi,
> 
> I am trying to build QGIS with QT6 on Ubuntu (tried 24.10 and 25.04),
> it builds without errors but when I run it, the following error
> appears:
> 
> Couldn't load PyQGIS.
> Python support will be disabled.
> 
> Traceback (most recent call last):
>   File "", line 1, in
>   File
> "/home/ale/dev/QGIS/build/Desktop_QT6-Debug/output/python/qgis/gui/__init__.py",
> line 25, in
>     from qgis._gui import *
> RuntimeError: qgis._gui cannot import type '���A� ' from
> PyQt6.QtCore
> 
> Python version:
> 3.13.3 (main, Jun 16 2025, 18:15:32) [GCC 14.2.0]
> 
> QGIS version:
> 3.99.0-Master 'Master', e717e3cd2b9
> 
> Python path:
> ['/home/ale/dev/QGIS/build/Desktop_QT6-Debug/output/python',
> '/home/ale/.local/share/QGIS/QGIS3/profiles/default/python',
> '/home/ale/.local/share/QGIS/QGIS3/profiles/default/python/plugins',
> '/home/ale/dev/QGIS/build/Desktop_QT6-Debug/output/python/plugins',
> '/home/ale/dev/gdal/desktop-install/local/lib/python3.13/dist-packages',
> '/home/ale/dev/gdal/autotest/pymod', '/usr/lib/python313.zip',
> '/usr/lib/python3.13', '/usr/lib/python3.13/lib-dynload',
> '/usr/local/lib/python3.13/dist-packages',
> '/usr/lib/python3/dist-packages']
> 
> I checked the QGIS/build/Desktop_QT6-Debug/output/python/qgis content
> and it looks legit.
> 
> PyQt6 installation also looks ok, importing core works ok, only gui
> does not work.
> 
> Any idea about what's going wrong?
> 
> --
> 
> Alessandro Pasotti
> QCooperative:  www.qcooperative.net [1]
> ItOpen:   www.itopen.it [2]
> 
> Links:
> ------
> [1] https://www.qcooperative.net
> [2] http://www.itopen.it
> 
> _______________________________________________
> QGIS-Developer mailing list
> QGIS-Developer at lists.osgeo.org
> List info: https://lists.osgeo.org/mailman/listinfo/qgis-developer
> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-developer