UI not updating in Qt Creator

After not having opened a project for while in QtCreator it often happens that changes made to the user interface in QtCreator are not coming through in the application after recompiling. This is then caused because I am now using a new version of QtCreator or I used to work on the project under Linux instead of Windows (or something like that). The problem is that QtCreator keeps changing where it puts the output of compiling the .ui file. Sometimes it is in the main project folder, sometimes where the .ui file is located and now it was changed into the folder with the impossible name yourProject-build-desktop-Qt_4_8_1_for_Desktop_-_MinGW__Qt_SDK__Release/Release (where it also puts the object files). And because previously it was stored in the project folder it will first find that old version. I guess removing the old version could work but I liked the solution I found here better: in the project file you can specify where the ui compilation output is stored:

UI_DIR = c:\YourLocation