Well, I tried to travel with a friend to the Lounge where the piano was available, so I could continue with the creation of music. I could not find it, my bad memory... However, I switched to world m...
Ideas
The workaround was to select other sim in the household and bring my first sim back. I suppose, it would be unplayable, if I had one person in the household. Btw, I have the latest Lovestruck pack.