What if QT tree is moved?

I have built QT in one directory and then, realizing that this directory is not where I wanted QT to be, physically moved the entire QT tree to a different directory.

Say, originally QT was build in C:\A and then moved to C:\B. More, C:\A had been removed and no longer exists.

Now, for example if I am calling QApplication::libraryPaths(), it returns two directories: C:\A and my app directory.

So, the question is: should QT be rebuild every time the QT tree is moved or there is some setting somewhere that reconfigures it?

You should rebuild it, but you don't have to. Read about qt.conf in your documentation. I'd suggest fixing the path though. Otherwise you'll encounter trouble in many places (for instance when using qmake).

Thank you. I already encountered the problem with qmake and had to fix it manually by changing makefile.