I install SQL Server 2012(64bit) on WIndows 7(64bit). After the installation, I start SQL Server Management Studio and click the login dialog, then I get an error message
"Object reference not set to an instance of an object. (Microsoft.VisualStudio.Platform.WIndowManagement)"
Then I click "OK". Then whenever I access any objects in SQL Server, I will get this error and failed. What is the problem?