Convert MDB to ACCDE

A legacy Access application may need an ACCDE front end when it must be distributed for data entry without exposing its forms, reports, macros, or VBA source. The editable MDB source remains with the developer while end users run the compiled deployment file.

What the MDB format is

.mdb is the Microsoft Access database format used by Access 2003 and earlier. Newer desktop versions of Access can open and convert many MDB files. An MDB can contain tables, queries, forms, reports, macros, VBA modules, relationships, indexes, and connection information.

Access developers and organizations commonly use MDB files for legacy line-of-business applications, archived databases, and split databases whose front end connects to a shared MDB or other back end. Access 2007 introduced the newer .accdb format.

What the ACCDE format is

.accde is Access's compiled deployment format for an ACCDB database. Access compiles the VBA project and removes the editable VBA source. It also prevents design changes to forms, reports, macros, and modules.

Users can normally add, edit, and delete records, and may be able to change table or query data and design depending on the application's structure and permissions. ACCDE is therefore an application-distribution format, not encryption and not complete protection for every database object. Keep the original MDB or ACCDB as the editable master.

An MDB cannot normally be saved directly as an ACCDE. MDB is associated with the older MDE deployment format; the usual route to ACCDE is MDB → ACCDB → ACCDE. Access 2007 and later can create ACCDE files, while Access 2003 and earlier create MDE files instead.

How to convert MDB to ACCDE

1. Back up the MDB and work on a copy. If it is a split database, convert only the front end; leave the linked back-end database in its existing format and verify that the copied front end can still reach it.
2. Open the copy in a desktop version of Microsoft Access 2007 or later. Run Database Tools → Compact and Repair Database first if the file shows corruption symptoms or has grown significantly.
3. Compile the VBA project. Press Alt+F11, choose Debug → Compile, correct every error, and use Tools → References to replace or fix any item marked “MISSING.” An ACCDE cannot be created successfully from a project with unresolved compilation problems.
4. Convert the MDB to ACCDB with File → Save As → Save Database As → Access Database (*.accdb). Save it as a new file and retain the original MDB.
5. Open the new ACCDB and test startup behavior, forms, reports, queries, macros, linked tables, and VBA routines. Check legacy ActiveX controls, API declarations, external references, and drivers before compiling the deployment copy.
6. Create the deployment file with File → Save As → Make ACCDE. Choose a new filename such as Application.accde; do not overwrite the editable ACCDB.
7. Test the ACCDE on the target computers. Match the Access version and 32-bit or 64-bit installation, and install the required ODBC drivers, ActiveX controls, referenced libraries, and network permissions. Access Runtime can run an existing ACCDE but cannot create one.

Tools and online conversion

Microsoft Access desktop is the appropriate tool because it performs Access-specific object validation and VBA compilation. LibreOffice Base and generic database converters may import or export data, but they do not create a valid Microsoft Access ACCDE deployment file.

Online conversion is generally unsuitable: an ACCDE requires Access compilation, and uploading an MDB can disclose table contents, connection details, macros, and application logic. No online service should be treated as a reliable substitute for local Access unless it explicitly documents MDB-to-ACCDE creation, supports the required Access version, and the database contains no confidential information. For normal production files, use local Access rather than an online converter.

Compatibility and limitations

ACCDE is not reversible to editable VBA source. Make all code, form, report, macro, and module changes in the source MDB or ACCDB, then generate a new ACCDE.

ACCDE does not encrypt data, secure linked back ends, or replace Windows, network, database, or Access security controls. Users who can access the back-end file may still access its tables directly. Apply file-system permissions and protect the back end separately.

A file created by a newer Access version may fail in an older version. Bitness differences can break Windows API declarations, ActiveX controls, and external references. Passwords, linked paths, custom ribbon settings, and unsupported legacy controls can also require adjustment after MDB-to-ACCDB conversion. Test with a copy of representative production data before distribution.