i updated my gpu driver to the latest (im using a radeon HD7870, win10_64bit) and the problem remains...
This time Cura crash after 20sec or so, before was crashing after 4 or 5sec.
i am reading now the cura log and see these lines:
2016-07-08 09:56:17,329 - DEBUG - Attempting to kill the engine process
2016-07-08 09:56:17,329 - DEBUG - Killing engine process
2016-07-08 09:56:17,331 - DEBUG - Engine process is killed. Recieved return code 1
2016-07-08 09:56:17,331 - INFO - Backend crashed or closed. Restarting...
2016-07-08 09:56:17,433 - DEBUG - Attempting to kill the engine process
2016-07-08 09:56:17,471 - INFO - Started engine process: C:\Program Files\Cura 2.1\CuraEngine.exe
2016-07-08 09:56:17,505 - DEBUG - Backend connected on port 49674
2016-07-08 09:56:31,718 - DEBUG - Autosaving preferences, instances and profiles
i notice that those lines are repeted every time the program crashes, maybe the problem is CuraEngine.exe?