I had the same kind of issue in Mixbus 4 the other day. Figured it was from the recent Win 10 major update since I read many others were having issues and I had never run into that before (finicky ASIO) . I just checked yesterday, and there was a new Win update avail. so I went for it. reinstalled ASIO also. I haven't checked it out again in Mixbus, but Samplitude seems to work fine today, so I'm happy.