Why does the application freeze or give an error when closing some windows or programs?

Question

Qt

An application built on Qt 5.10.1 under Windows sometimes hangs when closing child windows by clicking the cross. It doesn't show up in the debug output. This issue only occurs when testing on one of the Windows 10 laptops. The issue does not reproduce on other laptops. In which direction to dig and where to look for the problem, can this be due to incompatibility of the OS configuration or what software is installed on the problem laptop?
When building on Qt 5.11.1 for Mac, when the program is closed, an error window also appears. The only thing that is displayed in the debug console is the following messages:
15:43:57: The program has unexpectedly finished.
15:43:57: The process ended forcefully.
15:43:57: /Users/chi/Projects/quiz-smartcity/build-app-Desktop_Qt_5_11_1_clang_64bit-Release/quiz.app/Contents/MacOS/quiz crashed.
"There are still \"8\" items in the process of being created at engine destruction."
Closing occurs with the QML method: close();
Could this be because a destructor is needed for previously created objects or child windows

Answer 1

Anything can be. Run it under a debugger and see where it crashes. If you can't run it under a debugger, dump the process memory and see where it crashes. I have a suspicion that falls somewhere in the insides of Qt.