SQL2008 installation, "provider: Named pipe provider, ERROR:40-Unable to open connection to SQL Server" (. Net SqlClient Data Provider) "Error solution

Error message:

A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or could not be accessed. Verify that the instance name is correct, and that SQL Server is configured to allow remote connections. (provider: Named pipe provider, ERROR:40-Unable to open connection to SQL Server) (. Net SqlClient Data Provider)

Solution:

Workaround: Start All Programs->ms SQL Server-> Configuration tool->sql Server surface area Configurator, services and connections, surface area configuration, opening the database under the MSSQLSERVER node Engine node, select "Remote Connection", then choose "Use TCP/IP and named pipes at the same time", after determining, restart the database service can be.
If the error still occurs, then please check the code in the ConnectionString data source This property fills in the correct value is the default fill. \sqlexpress or replaced by computer name \SQLExpress ...

Also, check that the SQL Server network configuration is enabled for TCPIP connections, and check that the firewall is open for port 1433 .

Reference article:

1. NULL_BD

2. Zero_first , provider: Named pipe provider, error:40-cannot open a connection to SQL Server .

SQL2008 installation, "provider: Named pipe provider, ERROR:40-Unable to open connection to SQL Server" (. Net SqlClient Data Provider) "Error solution