Thanks a lot for your suggestions

I try to replicate it closing connection but there's always an exception that's catched

It happens again recently, with same symptoms, in a different source, but this time there was an exception:

"System.InvalidOperationException:

ExecuteNonQuery: Connection property has not been initialized.

en System.Data.SqlClient.SqlCommand.ValidateCommand(String method, Boolean async)

en System.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(DbAsyncResult result, String methodName, Boolean sendToPipe)

en System.Data.SqlClient.SqlCommand.ExecuteNonQuery() "

this exception was catched, in the catch block the method executes the tran.Rollback, but it still persisted data of the SP that uses begin tran ... commit tran

the exception happens when it tries to run this

Dim cmd2 As New SqlCommand("SET ARITHABORT ON", cn, tran)

cmd2.ExecuteNonQuery()

"cn" was initilialized from tran.Connection, at this point 5 SPs has been executed with the same tran instance, and before executing a 6th SP (that affects another tables on same DB) the "SET ARITHABORT ON" is executed

Now I would like to know what makes this Connection just dissappear and at same time why the tran.Rollback() doesn´t throw another exception

Dim cn As New SqlClient.SqlConnection("[valid connectionstring]")

cn.Open()

Try

... -- Lots of code, where in some function InvalidOperationException raises

tran.Commit()

catch as System.Exception

tran.Rollback()

throw

Finally

If not cn is nothing and also cn.state= ConnectionState.Open then

cn.Close()

End If

End Try

Any ideas?