I have this weird problem with iClone 5.5 that I didn't have before and I would like to know if someone else had this kind of problem and how it had been solved:

If I load a tree in a scene and try to save the project, everything seems normal, but when I reopen the project, the tree won't appear even if I can see, in the scene manager, that it is there. (If I open an old project with trees, I won't have this problem, except if I save the project again and reopen it afterward). If I try to add the same species of trees in the project I just saved and reopened, they won't be visible either (But I won't have this problem with other species, except that I won't be able to see them either if I save and reopen the project). I checked the visibility parameters, and everything is normal: pixel shading and normal display. Since I have this problem, I tried almost everything to solve it, I even reinstalled iClone 5.5 and it didn't solve the problem.