Welcome to OpenMandriva forums.
The first very strong recommendation is to read How to get better results when posting about problems.
OM-Welcome is developed by @rugyada so I can only speak in general problem solving terms. I do regard OM-Welcome as one of OM’s best efforts to make things more user friendly.
Post terminal output of the failure and/or journalctl output. You can run it from terminal (Konsole) with om-welcome.
To use journalctl start with journalctl --help. Maybe running this after the app crashes might produce something useful, journalctl | grep om-welcome. But it will probably just repeat the terminal output.
If the output is more than say 20 or so lines you can put the output in a .txt file and post that here.
From not always perfect memory I seem to recall this might have to do with certain graphic hardware so posting what the hardware in use is might be useful. To pull graphic hardware info inxi -G or for all hardware info inxi -F.