@koahnig said in set<int> in Qt creator and debugger: E.g. are there conflicts through the various files holding settings? There might be, you will probably at least need to reconfigure the project's kits (i.e. deleting the *.pro.user files). I'd try to load them directly first though, it might work fine. @koahnig said in set<int> in Qt creator and debugger: The same problem there. It's the same data structure, so no surprise at all, indeed.