First of all,sorry for not replying sooner and thank you very much for all your suggestions and help !
I opened the project in Safe mode and the play back worked normally ! In fact, as I described, when opened in no safe mode, there was a little window : SONARPDR and below there was the name of the Plugin "Master Violin" (the Violin from Gipsy East West) and a progression bar with step numbers 1 to 19xx, and, after this rather long step progression loading expires, the project and Sonar crashed, and I had to restart everything : computer, and all the VS700 system ...
In safe mode, I unselected the East West plugin, and things seem to be normal now. So, I presume that if I use the East West instrument, I have to FREEZE the plugin or bounce to audio track before I close the project ??
The problem is if the crash occurs suddenly when working on the project : It was the case with SAMPLETANK 3, but also, systematically with RAPTURE and DIMENSION PRO on another projects ! And for example, yesterday, I was jamming with BEATSCAPE which I know is at 32 bits version, and whereas I never had problems before with it, Sonar stopped ...
If someone has any idea ?
I made all the Windows updates as suggested and see if there are some improvements ! Will make a image backup system and go to the version D...
I forgot to say also that I have all the SONAR previous versions (from Producer 8.5 to X2). Apparently, I had never problems but maybe it could be best to remove them : For a clean remove : Do I have to go to the uninstall process in the Configuration Pannel of Windows 7 ? Or do I have to make another thing ?
Answering to Piet :
Did you have during mixing aso
-Anti virus off ? : Yes
-Anti spam off ? : Yes
- did you freeze tracks ? : Not systematically above all when I work late on a project; But never experienced too much problem and particularly with Kontakt 5, Spectrasonics, UVI...
- windows defender off aso? : I know that I have the Windows Firewall activated but it's all.
- sequencer,samples and projects on the same hd ? : No everything (c/system; plugin and samples; audio files) is separated in its own hd !
Have you optimized your box (windows) for music production? Yes, my computer is exclusively devoted to music production.
Which buffersize/ driver ? 256 (I think) and Asio with Roland VS 700 drivers (but unfortunately no more support for them)
Thanks again for your kind attention
Pierre