Qt 5 migration - Cannot open include file: 'ui_mainwindow.h'

Question

I\'m trying to migrate a simple project to Qt 5. The project was originally written for Qt 4, and it compiles fine there.

When compiling with Qt 5, however, I\'m get

Answer 1

What worked for me in the end was deleting both the Debug and Release build folders. What is strange is that I hadn't copied them initially, so I have no idea why it helped deleting them after they were first created.

But if anyone has this problem, try deleting the Debug and Release folders, as well as the .user file. This should force Qt Creator to reconfigure your project.