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

[Alessandro Pasotti]

Thanks, I'm using Python 3.13 (that comes with that Ubuntu version).

Now I'm trying with vcpkg ...


On Mon, Jul 21, 2025 at 5:35 PM pathmapper <pathmapper at posteo.de> wrote:

> 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
> >
> > _______________________________________________
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> > QGIS-Developer at lists.osgeo.org
> > List info: https://lists.osgeo.org/mailman/listinfo/qgis-developer
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>


-- 
Alessandro Pasotti
QCooperative:  www.qcooperative.net
ItOpen:   www.itopen.it
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