Click the "Select File" button above, and choose your ADU file.
You’ll see a preview, if available.
Click the "Convert file to..." button to extract text information.
Convert ADU to another file type
To convert ADU Dictionaries to another format, you need Addictive Spell Checker or other Settings software.
Convert a file to ADU
To convert other file formats to the "User Custom Dictionary" file type, you need software like Addictive Spell Checker or a similar tool.
About ADU files
The .ADU file extension represents an Addict User Dictionary file, created by the legacy Addictive Spell Checker component. This suite was primarily used by developers building Windows applications in Delphi or C++Builder to provide integrated spell-checking capabilities. Unlike the main dictionary file, the .ADU file is generated specifically for the end-user. It stores a list of custom words that the user has manually flagged to add to the dictionary, preventing them from being flagged as errors in future checks. A major disadvantage of the .ADU format is its proprietary, legacy nature. It is an isolated file format heavily locked into the Addictive Software ecosystem. Modern word processors like Microsoft Word or open-source spell-checking engines like Hunspell cannot natively read or import .ADU files. This creates annoying limits for users who are upgrading their software or migrating to newer systems, leaving their carefully curated custom dictionaries completely inaccessible. Users typically need to convert .ADU files to standard formats like .TXT, .DIC, or .CSV. Converting to .TXT or .CSV is highly recommended, as it extracts the raw text list of custom words without losing data. Once in a standard format, these words can be easily imported into modern spell-checkers or text editors. This file format is difficult to open or convert because it lacks standard header information and is designed solely to be read by the original Addict Spell Checker engine. Standard online converters fail to process it because it does not fit standard document formats. Just drag and drop your file to identify the format, view it, and convert it when possible. convert.guru can inspect the raw data inside the .ADU file to extract the hidden word list, allowing you to salvage your custom vocabulary.
Convert.Guru analyzes your ADU file, detects the exact format, and lets you read the text inside.
If you want to convert ADU file to MP3, WAV, AAC, FLAC, OGG, WMA, M4A, AIFF, OPUS, ALAC, APE or WV, you can use Addictive Spell Checker or similar software from the "Custom Spell Check Dictionary" category. In the File menu, look for Save As… or Export….
To convert MIDI, AAC, TTA, AU, WV, DTS, MID, FLAC, RA, MP3, PCM or WAV files to ADU, try Addictive Spell Checker or another comparable tool in the "Custom Spell Check Dictionary" category.
The ADU Converter Story
The history of Convert.Guru began over 25 years ago in California with Tom Simondi’s file-format database. A former contributor to Space Shuttle development and a software pioneer of the 1980s, Simondi established a trusted resource for file type analysis that was even referenced by Microsoft Windows XP. Today, we use modern technology to process and convert thousands of file formats while continually improving our ADU converter.