Issues with playback

When I use a vst-instrument for playback and exchange it with another multi-vst-instrument, there is no sound. The new vst doesn´t load any instruments. So, nothing is loaded and that´s why there can´t be a sound. I tried it with NotePerformer, Halion Sonic and with HalionSonic SE. Is it a bug?

That’s not a bug, that’s the way it is. When Dorico sets up a project, it knows what sounds to load into HALion Sonice SE and set up correctly the instruments and MIDI assignments. If on the other hand you load a VST-instrument yourself then you have to do this setup all by yourself.
However, at least for HSSE and NotePerformer there is a default template that does all the automatic setup for you, have a look in the Play Mode for the main menu item ‘Play > Playback Template’.

Thanks for your information, but the playback-functions seem to be generally a bit unstable. E.g the meters sometimes don´t react and other stuff.

The playback performance depends on the horse power of your machine, the complexity of your project, the audio interface/driver and it’s settings. So general advice can’t be given, unless you are a bit more specific.