Small update: just to try something different, I uninstalled my Anaconda distribution, reinstalled (this time using Miniconda), and created a new environment for Tracker (tracker-env).
The previously-mentioned “error on start-up” (QMimeDatabase…) disappeared. However, the other issues still occur (crash with file menu and errors with OpenCV), with the same error messages.
Versions are below (slightly different than before). All packages were downloaded from conda-forge channel (except Tracker of course), not sure if that matters?
conda 23.11.0
# Name Version Build Channel
python 3.12.1 h2628c8c_1_cpython conda-forge
pyqt 5.15.9 py312he09f080_5 conda-forge
qt-main 5.15.8 h9e85ed6_18 conda-forge
qtpy 2.4.1 pyhd8ed1ab_0 conda-forge
opencv 4.9.0 py312haba1e54_6 conda-forge
tracker 22.1.2 py_0 https://mfix.netl.doe.gov/etc.
numpy 1.26.3 py312h8753938_0 conda-forge
scipy 1.12.0 py312h8753938_2 conda-forge