Unable to connect to SQL Express "Error: 26-Error Locating Server/Instance Specified)

Question

I am at an loose end with one particular box that is running SQL Server 2008 R2 Express.

• Windows Firewall is configured to allow inbound TCP & UDP 1433, 14

Answer 1

I had a similar problem which was solved by going to the "SQL Server Configuration Manager" and making sure that the "SQL Server Browser" was configured to start automatically and was started. it works for me

Answer 2

In my case, I Installed SQL Express 2012 and the problem raise after I reboot my PC. I solved so:

I go to Services -> SQL Server (SQLEXPRESS) and I see that was stopped. I started and It's say an login error. In properties, Tab Log On, I change it to Local System account , then I can start the SQL service.

Then to test it, I go to SQL Server Management Studio and I connect to .\SQLEXPRESS and it works!

Answer 3

I found this url to be very useful: https://social.msdn.microsoft.com/Forums/sqlserver/en-US/2cdcab2e-ea49-4fd5-b2b8-13824ab4619b/help-server-not-listening-on-1433

In particular, my problem was that I did not enable the TCP/IP in Sql Server Configuration Manager->SQL Server Network Configuration->Protocols for SQLEXPRESS.

Once you open it, you have to go to the IP Addresses tab and for me, changing IPAll to TCP port 1433 and deleting the TCP Dynamic Ports value worked.

Follow the other steps to make sure 1433 is listening (Use netstat -an to make sure 0.0.0.0:1433 is LISTENING.), and that you can telnet to the port from the client machine.

Finally, I second the suggestion to remove the \SQLEXPRESS from the connection.

EDIT: I should note I am using SQL Server 2014 Express.

Answer 4

I had a Same Problem but i solved by Restarting the browser service in SQL CONFIGURATION MANAGER and removing \SQLEXPRESS from the instance name in the connection window.

Answer 5

It's security all about. Make sure you have double check your firewall (windows and anti virus) in some cases when you disabled av firewall and restart your computer, automatically windows firewall is active and it's still block your application. Hope this is helpful ..

Answer 6

Could you post the connection string you're using that's giving you trouble?
You might need to add the port number to the Data Source value, as omitting it can also produce SQL Error 26.

E.g.: Data Source=ServerHostName\SQLServerInstanceName,1433