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  amp  UDP 1433  1434  Windows Firewall is configured to allow outbound TCP  amp  UDP on any port  No other software AV FW is currently running    When I try to connect to xxx xxx xxx xxx sqlexpress  it times out with the following error      TITLE  Connect to Server      Cannot connect to xxx xxx xxx xxx SQLEXPRESS       ADDITIONAL INFORMATION       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   Microsoft SQL Server  Error  -1    I have checked that remote connections are allowed on the server   I have confirmed TCP IP is enabled and configured in SQL Server Configuration to allow connections on the external IP to 1433   I have also used Wireshark from my local machine and I can see requests for 1433 UDP going to the remote server   But using Wireshark on the remote server shows no inbound connection requests for 1433 UDP or anything from my external IP  with filtering to remote RDP from results    This makes me think it is a firewall issue   The server is hosted by an external company who have control over the PIX in front of our server   I need to troubleshoot this as much as possible myself as the hosting company have no clue what they are doing

User · Answer

The active firewall on the server might be causing this. You can try to (temporarily) turn it off and see if it resolves the issue.

If it is indeed caused by the firewall, you should allegedly be able to resolve it by adding an inbound rule for TCP port 1433 set to allowed, but I personally haven't been able to connect this way.

User · Answer

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

User · Answer

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   I came across this solution in the answer of this forum post  http   social msdn microsoft com Forums en-US sqlexpress thread 8cdc71eb-6929-4ae8-a5a8-c1f461bd61b4   I hope this helps somebody out there

User · Answer

All you need to do is to go to  the control panel   Computer Management   Services and manually start the SQL express or SQL server  It worked for me   Good luck

User · Answer

I got a similar problem with sql server   I have tried every thing but does not connect to database engine  amp  it shows error 26    First check if the database engine is running or not  by going into configuration manager  start   sql server  sql server configuration manager  On the right pane you should see the sql server  mss      should be running state with a green indication  IF the database engine is not running  simply uninstall sql server   format your system if possible and then download sql server 2012 and management    studio  from https   www microsoft com en-ca download details aspx id 29062    Install server first  make sure to add server on installation phase by clicking add server and then install management studio

User · Answer

Have you Disabled the VIA setting in the SQL configuration manager  If not  do disable it first  if VIA is enabled  you cannot get connected  and yes TCP must be enabled  Give it a try and it should be working fine    Make the changes only for that s particular instance name   Cheers

User · Answer

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

User · Answer

This really Works    i had verified lot of sites and finally got the answer  This may occurs when the master mdf or the mastlog ldf gets corrupt   In order to solve the issue goto the following path  C  Program Files Microsoft SQL Server MSSQL10 50 MSSQLSERVER MSSQL   there you will find a folder     Template Data       copy the master mdf and mastlog ldf and replace it in  C  Program Files Microsoft SQL Server MSSQL10 50 MSSQLSERVER MSSQL DATA folder    Thats it   Now start the MS SQL service and you are done

User · Answer

Here is a simple method to troubleshoot connection issues    Create an empty file called test udl using a text editor Double click the file test udl  then specify your connection properties Hit the  Test Connection  button

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I recently encountered the same issue however I am using Windows 10 Technical Preview Build 10041 and SQL Server 2014  Advanced    Follow the same advice from above      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    AND ----  That last line is important  It looks like to be Windows 10 specific  remove  SQLEXPRESS from your connection string  What was frusting was that SQL Management Studio connects just fine using either connection string  full or short   however Visual Studio only accepted the connection string without the  SQLEXPRESS

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

Go to SQL Server Configuration Manager   SQL Server Services   In Right Side window show all the servers which may stop  If you are using  SQLEXPRESS  then   Right click on SQL Server SQLEXPRESS  and start  After try to connect server    I had same problem but I resolved by these steps

User · Answer

If you have done anything but in spite of all couldn t connecting    In my case i have changed connection part splitting port     instead of this      The corresponding TCP port or pipe name is not specified in the connection string  such as Srv1 SQL2008  1433

User · Answer

press windows R open RUN Window  services msc    find SQL Server SQLEXPRESS  right click on that and start the service then check

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

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