1. Try installing Creator to "C:\Program Files (x86)\qtcreator-2.7.83" .
   The installer will not allow you to proceed because the path contains white spaces.
2. Instead, enter the path "C:\Progra~2\qtcreator-2.7.83".
   This is the same path using the 8.3 representation of the parent directory. The Installer will allow you to proceed.
3. Click "Next" and "Install" until the actual installation starts.
   Creator will show an error message: "Konnte Einstellungen des Installers nicht nach C:\Program Files (x86)\qtcreator-2.7.83/QtCreatorUninst.ini schreiben. Fehlermeldung: Zugriffsfehler" and cancels the installation.

The best solution would be if the Installer and Creator itself could handle such paths completely. If this is not possible, the Installer should check if the long filename of an 8.3 representation contains illegal characters and deny the path if it does.
A minimum workaround would be to not allow any tilde "~" in paths on Windows.