What is the ADI file format?
An .adi file contains a backup copy of a hard drive or other storage device created with Active@ Disk Image, developed by LSoft Technologies. An .adi file may also store a part of a split archive. The application supports the following storage devices:
- HDD,
- SSD,
- External hard drives,
- USB drives,
- Blu-ray, DVD, and CD optical media,
- Devices such as MP3 players, cameras, and other devices recognized by the operating system as mass storage devices.
Data in .adi files can be compressed using methods with varying compression ratios. An .adi file stores only the occupied sectors of a given storage device, which reduces the overall size of the backup. .adi files offer optional password protection and AES 128, 192, or 256-bit encryption. The encryption feature is available only in paid editions of Active@ Disk Image. A backup may be split into smaller files, named by appending sequential integers to the base filename - for example, a backup named Archive splits into Archive1.adi, Archive2.adi, and Archive3.adi. The tool supports both full and incremental backups.
Active@ Disk Image can also create raw disk images by copying data sector by sector; those copies use the .dim extension instead. The application runs on Windows and Windows Server. It includes a disk image restore function and allows mounting .adi images as virtual drives. A bootable rescue version is also available for creating backups outside of a running Windows environment.
Security & safety
RISK: MEDIUMAn .adi disk image is data, but it is a full snapshot of a drive - it can contain the entire contents (including deleted-but-recoverable data and credentials) of the imaged disk, so handle it as sensitive. Only download Active@ Disk Image from disk-image.com; "free .adi viewer" sites are often PUP/adware bait. Restoring an image overwrites the target disk, so verify the destination before restoring.
Format details
in a nutshell- ADIF amateur-radio log (.adi) - Plain-text Amateur Data Interchange Format log of ham-radio contacts (QSOs); opened/edited by logging software like Log4OM, N1MM+, ADIF Master. Very common meaning of .adi.
- AutoCAD device-independent plotter file - Legacy AutoCAD ADI plotter driver output for device-independent printing/plotting; obsolete.
- Approach data index / misc app data - Older apps (e.g. Lotus Approach index) reused .adi for data indexes.
Programs that open ADI files
Windows1 app
Active@ Disk Image
Freemium Open the .adi to restore, clone, or mount it as a virtual drive (Tools -> Open image) and copy out individual files. Free Lite edition for personal use. Technical details
deep spec| Developer | LSoft Technologies (Active@ Data Recovery Software) |
| Format type | Proprietary binary sector-based disk-image container |
| Primary application | Active@ Disk Image for Windows and Windows Server |
| Backup modes | Full and incremental backups |
| Sector selection | Only occupied sectors are stored; unallocated space is skipped to minimize archive size |
| Compression | Multiple compression methods with selectable compression ratio |
| Encryption | AES-128, AES-192, or AES-256-bit (paid editions only) |
| Password protection | Optional password lock on backup archives |
| Split archive support | Multi-part sets use sequential integer suffix naming (e.g., Archive1.adi, Archive2.adi) |
| Related raw-image format | .dim - Active@ sector-by-sector raw copy without proprietary container |
| Virtual drive mounting | Images can be mounted as virtual drives in Windows |
| MIME type | application/octet-stream |
| OS compatibility | Windows XP through Windows 11 and Windows Server editions |
| Bootable rescue environment | WinPE-based bootable media available for creating backups outside a running OS |
| Supported storage devices | HDD, SSD, USB drives, external drives, optical media (CD, DVD, Blu-ray), and OS-recognized mass-storage devices |
| Released | Active@ Disk Image (2000s); still current |
| Specification | www.disk-image.com |
ADI conversions
Community Q&A
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