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
Apple’s WWDC 2013 Keynote Now Available To Watch Online
It has been a very busy and exciting day for Apple announcing both iOS 7 and Mac OS X Mavericks.Apple has officially released the official video of todays keynote which took place at WWDC 2013.
The full 2 hour video is now available on Apples website here.