我在使用VS2010测试package的时候，突然发现sql server 链接到本地实例出错，出错信息如下：

“ A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server) (Microsoft SQL Server, Error: 2)”

后来我将VS2010关闭，然后重新连接Sql Server 2012，居然连接成功，原因我就不晓得了