How do I build a debug mode QT app that links to a lib built in release mode?

[Joachie]

you can built Qt with -debug-and-release configure key, that allows to use Qt in debug and release modes by adding CONFIG += release/debug flag in pro-file of your application.
so, you need:

Ok, I rebuilt as you suggested. So should all the libs now be using the non debug version of MSVCRT? Because the debug QT libs still appear to be using the debug version of MSVCRT.