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 releases OS X Lion 10.7.2 to Developers –
Apple has released has just released an edition to OS X Lion 10.7.2 to developers – build 11C48 – aswell as updating the 10th beta of iCloud for Mac. OS X Lion 10.7.2 is reportedly to be released at the same time as iCloud this fall.