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 Safari 5.1 for Mac OS X Snow Leopard and Windows
As part of OS X Lion released today, Apple includes Safari 5.1, an updated version of the company’s Internet browser that supports a number of improvements, some of which are tied into Lion’s new capabilities.
But Apple has also released Safari 5.1 for Mac OS X Snow Leopard and Windows, bringing some of the enhancements that don’t rely on Lion to those platforms.
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