I installed QtCreator in order to debug an external application using Valgrind.
I got the error message
qtcreator 4.8.0 Cannot start Valgrind Function Profiler (External Application) without a project
So I tried to create a new project and I saw that the default kit had an error because it could not find the qmake executable. I fixed it, then , and tried again to run Analyze->Valgrind [...] (external application) and it worked.
So the error message should have not complained about missing Project, it should have complained about Kit not being well configured, even if IMHO Valgrind has nothing to do with qmake.
Affects also 4.7.1. My system is Fedora 29