Well tried on another Computer, i do not have the software crash problem; i think it comes from Visual C++, ( yes its strange but since i installed it i got may crash ( from Mplab ( microchip software), and Picoscope ), that i did'nt have before , ( and when the soft crashes VC++ launch and want to debug the crashed soft)
I still need to plug unplug the device to make it work, but as soon as it works everything is fine.
Also i have another question, I never plug the power supply, i use the USB Bus to supply the picoscope , is that a problem ?
( the power supply i got with the picoscope do not work ).
Anyway i am very happy with the picoscope 3204