My setting: Python 2.7 with anaconda
Recently I have installed OpenCV 3.0 and when I try to do simple image display or I want to run python samples that come with OpenCV, there is a error message:

This application failed to start because it could not find or load the Qt platform plugin "xcb".

I have read many comments that I need to attach .so files to my project but I don't think it's the optimal solution since for most people it works out of a box. 
I have no clue what to do. I'm inexperienced. What comes to my mind is only to reinstall everything.
Okey, I have figured it out. 
During cmake I set flag -D WITH_QT=OFF since I read somewhere that it doesnt work for Qt5.x
python app - xcb plugin fail