When attempting to connect to SQL Express database from client machines, all (approx 5) work except 1. When setting up ODBC the appropriate server is being presented and if I take all defaults then the ODBC tests successful. However when trying to select the default database the database needed is not in the list. When troubleshooting I used the following command to determine which protocol is being used:
osql -Sxxx -E
On the working clients the error message refers to DBNETLIB however on the client not working the message refers to SNAC with named pipes.

What client control determines the protocol too use?

Thanks