@einstein said:
Hi, Samuel!
Hi Einstein! 
@einstein said:
I have reinstalled MS Visual C++ as you advised and now I can import stuff
Thank you!

@einstein said:
- The plugin always asks how big the imported model should be. It doesn't preserve its original size.
Scaling feature doesn't work for all formats. 
@einstein said:
- I was thinking of remesher tool as one working on selection, which would be more comfortable than remeshing entire model, as it goes now.
[...]
I tried to make it work with selection only but I don't know why it was VERY slow. So I gave up this idea...
@einstein said:
- When I import a model with multiple textures, I can only select one texture file and that texture is applied.
Sometimes I can but another time I cannot have all textures included. Some models may be badly textured but I'm almost sure that I tried importing the same chair as TutorialsUp did with success, while I didn't get both textures (only one). I'm attaching both OBJ and FBX version of the model.
I inspected attached model. Indeed, it doesn't reference any texture. In this case: you have to remap textures in a external software before importing model in SketchUp. Since v1.1.3, it's no more an issue.
Thank you!