ReWire : Quitting ReWire Client Applications
Quitting ReWire Client Applications
When quitting Pro Tools | First sessions that integrate ReWire client applications, quit the client application first, then quit Pro Tools | First.

If you quit Pro Tools | First before quitting ReWire client applications, a warning dialog may appear stating that “one or more ReWire applications did not terminate.” To avoid this, quit all ReWire client applications before quitting Pro Tools | First.