It’s incredible, I just remove guitar rig 5 32bits because it was not appropriate in the 64bits daw for cubase scan the good plug in 64bits. And it was a really NIGHTMARE !!! 10 times big stop of my PC and restartup … if just a plug make a pb = no warning but CRASH ! … why ??? I dare not touch anything even just a plug , because I know cubase will be eratic for scanning at the startup.
Please correct that it’s not the level of a professional DAW.
I add that these multiples crash remove the Vst 2 path … 
Ok I didn’t saw that it was reported here :
Hello,
This is pretty normal, I’d say.
The outcome of the crash pretty much depends on the plug-in crashing, the reason why it is crashing and the overall stability of the system.
If you add the path, then refresh and Cubase crashes, the new path won’t be remembered as Cubase crashes before saving the new path in the Preferences. If that is not the case, then it is possibly an account permission issue.
Please, send a support request via MySteinberg, listing your PC configuration, OS, Audio and MIDI devices installed and and detailed step-by-step description of how the crash happens and the dump files
Even better to check the system’s details is to provide an NFO file.
We also offer phone support for your country, in your language http://www.steinberg.net/en/support/support_contact.html
Ok thanks, I’ll do but for the moment my system is again stable so I don’t touch anything ! 
Ok I found the problem.
I have to disable an USB port which share an IRQ with my soundcard and I don’t know why this USB wasn’t deactivated !
Now it will be very more stable
