Access Database with multi users?

Access is not designed to be used by multiple users. Instead of investing more time trying to use Access, your time is better spent converting to something else, such as SQL Server. You can install SQL Server in every system that you need to use the databases from and connect with SQL Servers in other systems but I don't think you can do that using Access databases.
 
Sometimes developers use the tools they think are the easiest, then end up spending a lot of time getting it to work when it would be easier to use something else that they thought would be more difficult.