An ACCDE file is a database file format created by Microsoft Access. It is a compiled version of an Access database with all the objects and code compressed into a single file. The ACCDE file is designed to protect the database, prevent changes to its design and prevent unauthorized access to its data.

When an Access database is converted to an ACCDE file, all of its code is compiled, making it unreadable and uneditable. This means, any macros, VBA code, or custom functions cannot be modified. Additionally, users cannot add new objects or modify the existing ones. This file format is ideal for sharing a database with users who just need to view and manipulate data, but not modify the application.

One of the major advantages of using an ACCDE file is that it improves the performance of the database. As the Access database is functioning from a single compiled ACCDE file, the database loads faster and runs more efficiently. Moreover, since the code is protected, the users cannot mistakenly break or disrupt the code, which ensures that the database will continue to run correctly.

ACCDE files are commonly used by Access developers to distribute their work. By converting their database to an ACCDE file, developers can encrypt their code and properties. This not only protects their intellectual property but also provides their clients with a finished product that they can use right away.

In summary, Access databases that are converted to ACCDE files are run-only with its code compiled and protected. This file format provides an easy way to share Access databases with clients or end-users who need to interact with the database, but not alter it. It also protects proprietary designs and code, increases database performance, and is a widely accepted file format in Microsoft Office environments.