Edit: After half day, my wife’s Mac started having the same problem. I have then applied the solution that I found in the Apple
How To Close Unresponsive Programs On A Mac
When switching from Windows to Mac the change can be really strange and complicated to get your head around. So we have started a series which aims to get you to be able to use a Mac with no problems at all.
This series is for the beginners and we understand this is not for everyone. In the third episode we show you how to close unresponsive / crashed or frozen programs on a Mac. If you have got anything specific you would like us to cover on our Mac beginners guide by getting in touch on Twitter @MacReviews or email Tips@MacReviews.com