For better performance, SQL Express database can be scaled up to SQL Server without code modifications. BillQuick includes a utility to convert your Microsoft Access database to Microsoft SQL but requires a new license key. All editions of SQL Server 7.0 can be upgraded from an existing MSDE/SQL Express solution. Another way to upgrade an MSDE/SQL Express solution is to use SQL Server 7.0 Enterprise Manager from a SQL Server machine to connect to the MSDE/SQL Express. Once connected, data can be transferred from it to SQL Server.
Prior to upsizing your BillQuick database to SQL, please do the following:
- Back up your database.
- Ensure you have adequate disk space. Multiply the size of your BillQuick database by two and reserve that amount of space on your SQL Server.
To upsize to BillQuick Enterprise:
1. After installing Microsoft SQL and BillQuick Enterprise, open your existing BillQuick 20xx database.
2. From the File menu, select 'Upsize to SQL Server'. 
3. In the BillQuick SQL Database screen, enter the SQL Server Name, User ID, Password and Database Name of the new BillQuick Enterprise database. The User ID must have system administrative (SA) rights on the SQL Server. 
4. Enter or browse for the location where these SQL database settings will be saved. Click OK.
Note: Sometimes, due to slow network speed or server, the upsizing may not be successful. If so, use SQL Server Enterprise Manager to delete the database and try again.
Read the BillQuick Help>Start-Up>Installation>SQL Database>How Do I Upsize to SQL for more details.