If you develop an application for use inAccess 2000 or later, compiling the application in Access 2000 before distributing it has two advantages:

Better performance in Access 2000. When you open a Microsoft Access 2000 file for the first time in Access 2002 or later and save changes to any module (module: A collection of declarations, statements, and procedures stored together as one named unit. There are two types of modules: standard modules and class modules.) — including a module containing the code behind a form or report — Access increments the version of the Visual Basic project (project: The set of all code modules in a database, including standard modules and class modules. By default, the project has the same name as the database.). This prevents Access 2000 from loading the compiled version of the Visual Basic project. As a result, the application might run more slowly in Access 2000. To ensure optimal performance of an Access 2000 file that you will use in Access 2000 or later, compile and save the application in Access 2000.

Preventing errors caused by differences between versions. The object libraries that ship with Access 2002 or later contain some new objects, methods, properties, and events that aren't available in Access 2000. Using one of these new objects, methods, properties, or events in Access 2000 will result in a compile error. If you want to use an Access file in Access 2000 or later, compile and save the application in Access 2000 to ensure that the objects, methods, properties, and events in your code are available in both versions.

When you open a Microsoft Access version 2.0 database, an Access 95 database, or an Access 97 database in Access 2002 or later, the Convert/Open Database dialog box asks you to choose between converting and opening (enabling) the Access database. When an Access 2002 or later user enables the database, Access maintains the original format so that users of previous versions of Access can continue to use the database. For example, if a shared database is created in Access version 2.0, it can be used with Access version 2.0 and enabled in Access 2002 or later.

When you use an enabled Access database in Access 2002 or later, you can view database objects (database objects: An Access database contains objects such as tables, queries, forms, reports, pages, macros, and modules. An Access project contains objects such as forms, reports, pages, macros, and modules.) and add, delete, or modify records in Access 2002 or later, but you can't modify the design of objects. To modify the design of existing objects or to add new objects, you must open the file in the previous version of Access.

Size of an enabled Access database Your Microsoft Access database may increase in size when you enable it. If you have already enabled a database in a previous version of Access, and if you enable it again in Access 2002 or later, the size of the Visual Basic project (project: The set of all code modules in a database, including standard modules and class modules. By default, the project has the same name as the database.) will increase even more. In rare cases, you may have enabled a Access version 2.0 database in Access 95, enabled it again in Access 97, and enabled it again in Access 2000 or later; in this case, the Visual Basic project must store information in the format of each version.

Enabling an Access database employing security measures    If your Microsoft Access database employs these security measures, you can make sure that it retains its security level by recreating the workgroup information file in Access 2002 or later. If you cannot recreate the workgroup information file, you can use the Workgroup Administrator to join the security-enabled database's previous-version workgroup information file. However, it is recommended that you convert the workgroup information file to Access 2000 file format before you join it. In Access 2002 or later, you can use a workgroup information file that was created in a previous version; however you can't use a workgroup information file created in Access 2002 or later in Access 97 or earlier.

As long as you use the database with its original workgroup information, it retains all its security measures except permissions for the modules. In Access 2000 or later, you can't use user-level security (user-level security: When using user-level security in an Access database, a database administrator or an object's owner can grant individual users or groups of users specific permissions to tables, queries, forms, reports, and macros.) to help protect modules. However, you can help protect Visual Basic for Applications (VBA) code with a password.

Code compatibility    Microsoft Access 2000 or later does not support the DAO (Data Access Objects (DAO): A data access interface that communicates with Microsoft Jet and ODBC-compliant data sources to connect to, retrieve, manipulate, and update data and the database structure.) 2.5/3.x compatibility library. If you attempt to enable an Access database in which the code contains older versions of DAO objects, methods, and properties that depend on the DAO 2.5/3.x compatibility library, you receive a message that there were compilation errors during the enabling of the database. Before you enable the Access database, update the code so that it does not depend on the DAO 2.5/3.x compatibility library.

New style of toolbars and menu bars    Microsoft Access 97 or later supports a new style of toolbars and menu bars. When you enable an Access 95 database in Access 2002 or later, custom toolbars are converted to the new style but the conversion isn't saved. Custom menu bars are interpreted as the new style menu bar, but the menu bar macros are not converted and continue to be supported.

You can upgrade parts of an Access database to Access 2002 or later so that it can take advantage of many new features, and still use the original unchanged database for users of previous versions of Microsoft Access. Users of all versions can share the same data.

You can use this strategy whether your Access database is in one file, or is a front-end/back-end application (front-end/back-end application: An application consisting of a "back-end" database file that contains tables, and copies of a "front-end" database file that contain all other database objects with links to the "back-end" tables.). To use an Access database that is one file in several versions of Microsoft Access, convert it to a front-end/back-end application. The data in the back end remains in the oldest version of Microsoft Access, and you use a front end that has been converted to Access 2002 or later. To use a front-end/back-end application with several versions of Microsoft Access, you convert the front end of the application.

Whether you should convert or enable a Microsoft Access file (Microsoft Access file: An Access database or Access project file. An Access database stores database objects and data in an .mdb file. A project file doesn't contain data and is used to connect to a Microsoft SQL Server database.) depends on which versions of Access users have upgraded to.