fatal error: QMainWindow: no file or directory

[Ichizaemo]

Hi, I can't build my project with the Error ' :
fatal error: QMainWindow: no file or directory #include <QMainWindow>

Earlier in the morning I just installed QT 5.9.1 and I am working on Ubuntu 17.04

[sierdzio]

Do you include widgets module in your .pro file?

QT += widgets

[Ichizaemo]

yeah but I had to remove all the library and install a new version

[sierdzio]

So it is working again for you?