QTemporaryFile with name template does not work on OS X Sierra when app is launched from finder. When app is launched from Terminal.app it works fine.

Example app in attachment. To reproduce build attached app on OS X Sierra, run application from terminal. After that run application from finder (it will be in out/release directory)

In first case you should get two message boxes with temporary file path. In second case you should get one message box with temporary file path and second with error "Permission Denied"