This qmake error occurred when porting code from Qt Creator under Ubuntu to Qt Creator under Windows.
The compile output is:
No valid Qt version set. Set one in Tools/Options Error while building project CppPortQtCreatorUbuntuToQtCreatorWindows1 When executing build step 'QMake' Canceled build.
Following this output, check Qt's version (png). In this case, the path to qmake was still to its Ubuntu location. So, set it to a valid location (png).
