Hi,
I tried for days to fix the problem, but no way. In Windows 8.1 I installed the weekly build of open3d with python 3.9 and it worked, also if with some interference with other addons, until i made the blender update to 2.93.3 . After that Blender exit always if I try to activate the addon. Previously it strangely made some python script to give errors and then I had to deactivate the addon in Blender 2.93.2.
Any suggestion would be appreciated, thank you