AD1 File

What are AD1 files and how to open them

Are you having problems opening an AD1 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 AD1 files.

What is an AD1 file?

An .AD1 file is an AccessData Forensic Toolkit Device Dump file.

AccessData Forensic Toolkit Device Dump is a forensic image container created by AccessData's FTK Imager (or related AccessData tools). It is used when an investigator wants to preserve specific files, folders or logical content - not a full sector-by-sector disk copy. The format lets you collect pertinent evidence items (user documents, logs, specific paths) while keeping folder structure and file metadata intact.

FTK Imager writes .AD1 files via its Logical Image or Custom Content Image features. The user selects files or directories to include; the tool captures these with original timestamps, ownership and attributes. .AD1 supports optional encryption under AccessData's ADCRYPT scheme. After creation the images are used in forensic analysis and Examination workflows by AccessData's FTK, Summation, eDiscovery, and other products. Earlier versions produced AD1v3; newer ones (from FTK/Imager 3.4.1+, FTK 6.0+, Summation/eDiscovery 6.0+) now use AD1v4, which has upgraded compatibility and internal structure.

Internally, an AD1 container holds a catalogue or tree of files and directories (paths), per-file metadata (such as timestamp, file attributes), and the file contents often stored in compressed blocks (for example using zlib) across one or more segment files (often .ad1, .ad2, …). It also includes hash values (MD5, SHA-1) for integrity verification. If encrypted, the ADCRYPT header appears early (signature "ADCRYPT" at byte offset zero) and only a small unencrypted portion is visible before encryption takes over the rest of the data.

How to open AD1 files

Important: Different programs may use files with the AD1 file extension for different purposes, so unless you are sure which format your AD1 file is, you may need to try a few different programs.

While we have not verified the app ourselves yet, our users have suggested a single AD1 opener which you will find listed below.

Last updated: August 17, 2026

Various apps that use files with this extension

These apps are known to open certain types of AD1 files. Remember, different programs may use AD1 files for different purposes, so you may need to try out a few of them to be able to open your specific file.

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