I've tried to change the odbc driver using JET, still they said : Couldn't use file, File is In use. Data source name not found and no default driver specified Unable to connect to the server ''.In the above case, it was SQL Server 2005. When creating a datasource you have to take care to use the correct tool in respect to which client programs will be using the datasource. Data source name not found and no default driver specified.Microsoft odbc driver manager data source name not found vb6 5.