Ok.
Now i’m using the .922 as suggested by heckflosse (see before)
When i click on Rt shortcut, nothing appears but i see the process in activities management window.
I wait some minute and Rt main window appears. The number of thumbnails (if you intend pictures preview) depend by the folder. Can be 2 or 300, but i’m sure that this is not the main problem because Rt works fine.
Anyway, if i try to open Option window, it keeps some other minute.