ADB File

What are ADB files and how to open them

Are you having problems opening an ADB file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your ADB files.

What is an ADB file?

ADB files have multiple uses, and CorelCENTRAL Address Book is one of them. Read more about the other uses further down the page.

CorelCENTRAL Address Book

ADB is short for Address Book, and these files contain appointments, contacts, emails, and other data entered through CorelCENTRAL, a Personal Information Management application by Corel. The address book imports all your current clients into its database from sources like your Windows or MAPI address books. You can even synchronize your CorelCENTRAL with your Microsoft Outlook account; this allows for CorelCENTRAL to remind you of important meetings.

How to open ADB files

Important: Different programs may use files with the ADB file extension for different purposes, so unless you are sure which format your ADB file is, you may need to try a few different programs.

While we have not verified the apps ourselves yet, our users have suggested ten different ADB openers which you will find listed below.

Last updated: August 17, 2026

All known file formats using extension .ADB

While CorelCENTRAL Address Book is a popular type of ADB-file, we know of 2 different uses of the .ADB file extension. Different software may use files with the same extension for different types of data.

HP Phone/Database/Note database

These files are used on Hewlett-Packard's HP 100LX and HP 200LX palmtops for storing personal information such as appointment books, phone books, general databases, and notes. It holds structured records arranged according to a database definition (or template) chosen by the user. Each record consists of multiple fields (for example name, phone number, address, note) and one special field called Note which can hold a large block of text. Records are created, edited or deleted via the palmtop's built-in PIM applications.

Files of this type are written by the HP 100LX / 200LX Operating System or its built-in Phone Book, Database, Note-Taker and Appointment Book applications. They are used whenever you save your phone book, notes or define a custom database on the palmtop. Users may also translate or export these files to comma-delimited form for use on a PC using the HP Connectivity Pack's Translate/Merge features or third-party utilities. The format supports large note fields (about 32 KB), up to ~5,000 records (limited by RAM or disk capacity), up to 99 fields in a database structure spanning up to 4 pages, and categories and subsets for viewing and organising records.

Internally the file begins with a signature "hcD" in ASCII at offset 0 (bytes 0x68 0x63 0x44 00 in hex), and contains the string "ALL FIELDS" somewhere in its structure. The extension .adb is standard for Appointment Book files, while .gdb, .pdb, and .ndb correspond to general database, phone book, and note taker types using essentially the same file structure.

Various apps that use files with this extension

These apps are known to open certain types of ADB files. Remember, different programs may use ADB files for different purposes, so you may need to try out a few of them to be able to open your specific file.

Help us help others

File.org helps thousands of users every day, and we would love to hear from you if you have additional information about ADB file formats, example files, or compatible programs. Please use the links below or email us at submit@file.org to discuss further.