The question here is the same as mine but the solution there is not working for me. I am using QtCreator 2.4.1 on Windows 7. When i try to debug a simple hello world app the
Depending on the version of Visual Studio you have installed you can find the CDB.exe in different locations. Check if it is available in your system by searching in C:\ drive.
In my case I have Windows 7 (x64) with Visual Studio 2012 Express and Visual Studio 2013 installed and I had to install Microsoft Windows SDK for Windows 7 available here in order to have CDB.exe in my system. After the install, QT Creator was able to detect CDB.exe in this location: C:\Program Files\Debugging Tools for Windows (x64)\cdb.exe.
The only thing you need from the SDK is the Common Utilities | Debugging Tools For Windows.