For those who have installed the beta2 version of Qt5, qmake from beta2 will still be shown in the auto-detected qmake in Qt Creator.

Steps:
1 - Install beta2
2 - Open Qt Creator->Preferences->Build and Run
3 - qmake from beta 2 is auto-detected
4 - uninstall beta2
5 - install RC1 package (i.e. 351)
6 - qmake from rc1 is auto-detected as expected

problem => qmake from beta 2 is still auto-detected while it does not exist anymore.

This can be worked around by moving %APPDATA%\QtProject to %APPDATA%\QtProject_old (QTBUG-28222)

This could be listed as a known issue until this is fixed.