Qt error: LNK1181: cannot open input file 'debug\main.obj'

Question

Qt creator was working well, but suddenly shows a problem error: LNK1181: cannot open input file \'debug\\main.obj\'.
This problem shows always with any typ

Answer 1

The problem has been solved.

The cause of the problem was when creating a new project (GUI or Console), all source files that belong to this new project take a wrong extension ex: main.cp, but the correct extension is supposed to be ex: main.cpp. And when change all the source files extension from .cp to .cpp worked fine.

Or change the default source file extension from [Tools -> Option -> C++].