what about house requirements, the release notes mentioned that the requirements have changed a bit so if you don't meet these requirements then i suppose that could also cause the NPCs to not spawn.
well that is a bit more clarity than the other posts. they only mention the NPCs not being there, they never mentioned them disappearing while on screen
While I do like the trainer and what it offers, not everything it has is necessary. If it's item and coin manipulation your after than you can just as easily do so with the TerrariViewer mod, which also lets you send your HP and MP to over 1000