DBConvert/ DBSync for Access and Microsoft SQL Server are powerful cross database migration tools for upsizing and synchronization of Access x86/x64 data to MS SQL Server.

Generally the number concurrent users for an Access database is limited to maximum of 10-20 users. Access does not provide the level of security and reliability that SQL Server does. Besides, Microsoft said, that the MS Jet Database Engine that is used in MS Access, has entered a state of functional deprecation. They recommend using MS SQL Server Express or MS SQL Server Compact Editions instead for new database applications as a backend.