Hi @Verena1 ,
We have not tested things thoroughly with Rhino 8 WIP yet and maybe things have changed so much that we’ll have to make some updates but, assuming things have not changed too much, have you tried checking your IronPython path as noted in this topic?
Do you see the ladybug_tools folder listed in your Rhino 8 IronPython search path?
If not, then you can try manually adding the ladybug_tools folder to the path as described in that post. If that still does not work, maybe someone from McNeel could provide some insight in terms of how IronPython is set up in Rhino 8.