How can I solve this error?

eefesafak

There is no syntax error. But I see this error.
[Makefile:797: ui_mainwindow.h] Error 2

mrjj

Hi
it seems something is up with ui_mainwindow.h

Did you try completely delete the build folder so all files are regenerated (including ui_mainwindow.h)

A.A.SEZEN

[Makefile:797: ui_mainwindow.h] Error 2

Try this way and compile again.
main menu->build->clean

Maybe you should delete the build folder completely and compile it again.
I think it should work.