Sqlexception: System.data.sqlclient.sqlexception (0x80131904)

I wrote a code in C#, which works great at my computer, with Windows 7 (MS SQL Server 2008) but not at the other with Windows Vista (MS SQL Server 2005). I can not change system on

Solution 1:

This error is not a login issue. It's not a matter of invalid credentials. You would get a different error message for that. This error message simply means it cannot find either the server (probably) or the database in the connection string.

There is a open source program on CodePlex you can download to testing connection string etc. You can find it here. This should help you determine where/what the problem is.

Solution 2:

To me it looks like in connection string you are calling your server by the machine name and SQL server is not enabled with Named Pipes. The solution to the problem is: either enable the named pipes in SQL Server configuration or in connection string provide the IP Address of the SQL Server instead of name.