microsoft sql server error 26 – Error Locating Server/Instance Specified

This is an instance specific error.This error does not Occur for default instances.This occurs mainly as a result of missing responce from the sql server browser service.

When you try to connect to an instance of SQL Server then you get the following error:

Cannot connect to SERVERINSTANCE.


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: SQL Network Interfaces, error: 26 – Error Locating Server/Instance Specified) (.Net SqlClient Data Provider)

Additional information would be as follows:
Error Number: -1
Severity: 20
State: 0

The following post helps you understand the basic reasons for network related errors in sql server Causes For Network Related Errors in SQL Server

Fix for this error:

  • Check and confirm if the server name is correct, Contact the server admin to validate this
  • Check and confirm if the instance name is correct, Contact the server admin to validate this
  • Add port number to the sql server instance name, Contact admin for the prot number of the instance
  • Ping the server and check if the server is up and running
  • Contact the admin of the server for additional help on this error

If you are the admin of the server on which the instance is running then

  • Check if the SQL Browser service is running on the server.
  • Give the browser service necessary permissions by giving it a logon account for running the service.
    Following are the minimum necessary permissions for the account:
    – Should have permission to log on as a service
    – Should have permissions to read and write the SQL Server registry keys, in order to fetch the port details etc.
    Also this security context of this account should be of a low privileged user, this minimizes exposure to attacks through the network.
  • Check if the instance is not hidden
  • Add exception to the sql browser service and sql server service in the firewall
  • Try connecting to the instance from the server using SSMS, if it is connecting then try connecting to the same instance from some other machine in the same doman
  • If you have portqry in the system then you can use the following command to query the port of the server.
    portqry -n SERVERNAME -p UDP -e 1434
    portqry can be downloaded from
    PortQry Command Line Port Scanner Version 2.0

Complete error in SQL Server Management Studio – SSMS:

[xml]
===================================

Cannot connect to SERVERNAMEINSTANCENAME.

===================================

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: SQL Network Interfaces, error: 26 – Error Locating Server/Instance Specified) (.Net SqlClient Data Provider)

——————————
For help, click: http://go.microsoft.com/fwlink?ProdName=Microsoft+SQL+Server&EvtSrc=MSSQLServer&EvtID=-1&LinkId=20476

——————————
Error Number: -1
Severity: 20
State: 0

——————————
Program Location:

at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection)
at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj)
at System.Data.SqlClient.TdsParser.Connect(ServerInfo serverInfo, SqlInternalConnectionTds connHandler, Boolean ignoreSniOpenTimeout, Int64 timerExpire, Boolean encrypt, Boolean trustServerCert, Boolean integratedSecurity, SqlConnection owningObject)
at System.Data.SqlClient.SqlInternalConnectionTds.AttemptOneLogin(ServerInfo serverInfo, String newPassword, Boolean ignoreSniOpenTimeout, Int64 timerExpire, SqlConnection owningObject)
at System.Data.SqlClient.SqlInternalConnectionTds.LoginNoFailover(String host, String newPassword, Boolean redirectedUserInstance, SqlConnection owningObject, SqlConnectionString connectionOptions, Int64 timerStart)
at System.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(SqlConnection owningObject, SqlConnectionString connectionOptions, String newPassword, Boolean redirectedUserInstance)
at System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, Object providerInfo, String newPassword, SqlConnection owningObject, Boolean redirectedUserInstance)
at System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection)
at System.Data.ProviderBase.DbConnectionFactory.CreateNonPooledConnection(DbConnection owningConnection, DbConnectionPoolGroup poolGroup)
at System.Data.ProviderBase.DbConnectionFactory.GetConnection(DbConnection owningConnection)
at System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory)
at System.Data.SqlClient.SqlConnection.Open()
at Microsoft.SqlServer.Management.UI.ConnectionDlg.Connector.ConnectorThread()

[/xml]

References: MSDN

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