.ACCDC File Extension

Packaged database file created by Microsoft Access, a desktop relational database management system (RDBMS) application; contains a digitally-signed database package that was created from an original .ACCDB database file.

ACCDC files allow users to distribute trusted database files over the Internet. After receiving an ACCDB file, you can import it back into Access by selecting File → Open.... When importing the file, you will be prompted and asked whether or not you trust the signed certificate from the publisher.