Instance failure, in System.Data in sql 2012

Question

On Win Server 2012 Standard I have a C# app that runs fine with sql 2008 express. When I installed sql 2012 express I get "instance Failure" source: System.data. when the following LYNQ query executes:
//MessageBox.Show("Starting GetInitialPortStatus.");
db =new
DataClasses1DataContext();   //establish
dataconnection to CALMasterSQL
// 2. Query creation.
var PortsQuery =from
portrecord in db.Channels
select portrecord;
// 3. Query execution.
int count = 0;
// MessageBox.Show("Starting >portrecord in PortsQuery<.");
foreach (var
portrecord in PortsQuery)           
// add rows to the grid for each record in the database Ports table
Otherwise the app works fine. The closet fix in the forum I could find was to run
exec sp_configure 'user instances enabled',
1.
Go
Reconfigure
Which I did but no change.
How can this be corrected. It seems like it is a known issue but no fix for sql 2012?
Thanks
Morris
Thank you Morris

Answer 1

Thanks for your reply.
The connection string is:
<add name="CMMainWindow.Properties.Settings.CALLMASTERConnectionString"
            connectionString="Data Source=HLA2012\\SQL2012EXP;Initial Catalog=CALLMasterSQL;Integrated Security=True;Connect Timeout=5"
            providerName="System.Data.SqlClient" />
The SQl instance is call "SQL2012EXP". There is also SQL 2008 Express on the same machine called SQLExpress.
Both engines work fine in every other way.
Thanks
Morris
Thank you Morris
Hi MoCoder,
According to your description, if it contains a double-slash between the server name and the database instance name in your connection string, it should be localhost\SQLEXPRESS. There is a similar issue about instance failure when connecting to SQL Server
Express in C# application. You can review the following article.
http://www.hanselman.com/blog/FixingInstanceFailureWhenConnectingToSQLServer2005Express.aspx
In addition, Make sure your SQL Server instance(MSSQLSERVER) is running via the services management console.
Thanks,
Sofiya Li
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Sofiya Li
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