Audio Playback Disappears On Reopen Of Project

Everything was working great. Did an audio export. Mix was OK, but I really needed Wavelab to finish, so before mixing the next project, I bought and installed Wavelab Elements. Now, none of my audio tracks will playback in Cubase LA AI. I changed nothing in the projects. Even the project I had previously exported successfully will not playback audio tracks now in Cubase.

Any ideas?


Is WaveLab running at the same time as Cubase?

If not, double-check the Studio > Studio Setup > VST Audio System (what driver do you use?) and the Studio > Audio Connections > Outputs (is it connected?), please.