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 Confirms WWDC Keynote To Take Place Monday, June 10th
Apple has today confirmed that the famous WWDC keynote will take place on June 10th as previously expected. This is standard for Apple to kick of the conference with keynote so the developers have the rest of the week to ask Apple employes questions about the new software and how it may affect their apps.
Apple has already said that it will be debuting the new versions of iOS which is believed to be iOS 7 and also Mac OS X 10.9 at this years developers conference. Tickets for WWDC 2013 sold out in less than 90 seconds but don’t worry Apple Fan Site will have live coverage of the event, here.
SourceAll Things D