If I shut down and restart it opens as expected. The thing is I would have assumed that some other program is not releasing the the asio driver but Wavelab 6 opens ok. Wavelab7 just gives me the rotating disc under Win 7 then nothing.
Maybe, for some reasons, WaveLab must be stating in memory after quitting. In that case, remove the process from the Task manager, before launching WaveLab again.
Thanks Phillipe I’ll try that next time.