Click the "Select File" button above, and choose your MUL file.
You’ll see a preview, if available.
Click the "Convert file to..." button to extract text information.
Convert MUL to another file type
To convert your MUL file to another format, you need UO Fiddler or other Game software.
Convert a file to MUL
To convert other file formats to the "Multiplexed Archive" file type, you need software like UO Fiddler or a similar tool.
About MUL files
The .mul extension stands for Multiplexed, a generic container format used to pack multiple data streams into a single file. Users typically encounter this file in three distinct scenarios, each requiring different tools.
Ultima Online Assets: Historically, .mul files store the massive static data libraries (maps, gumps, art, and sound) for Ultima Online. These are proprietary archives. You cannot open them with standard image viewers. Modders and server admins need to extract these files to BMP, TIFF, or WAV to edit game assets. Newer clients use the UOP format, but legacy servers still rely on .mul.
Crystal Dynamics Game Audio: In games like Tomb Raider: Underworld and Deus Ex: Human Revolution, .mul files act as "BigFiles" containing interleaved audio and cinematic video. Gamers often want to convert these to WAV or MP3 to extract soundtracks or dialogue. Standard audio players will see these as corrupt data because they contain a proprietary header and multiplexed streams.
DVR/CCTV Video: Some Ingenient Technologies and older DVR systems save multi-channel security footage as .mul. These are raw streams that standard media players like Windows Media Player cannot decode. To view them, you must convert the stream to MP4 or AVI using specialized DVR conversion utilities or a properly configured VLC media player.
Common Friction Points:
Opacity: The file gives no clue as to what is inside (audio vs. map data vs. video).
Size: Files can range from a few megabytes to several gigabytes.
No Native Support: Neither Windows nor macOS can open these natively.
Convert.Guru analyzes your MUL file, detects the exact format, and lets you read the text inside.
If you want to convert MUL file to EXE, ISO, BIN, CUE, PAK, WAD, PK3, PK4, BSP, MAP, SAV or DAT, you can use UO Fiddler or similar software from the "Game Asset Container" category. In the File menu, look for Save As… or Export….
To convert MOD, BIN, CFG, SCX, DAT, MPQ, LOG, CUE, INI, EXE, SCM or ISO files to MUL, try UO Fiddler or another comparable tool in the "Game Asset Container" category.
The MUL 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 MUL converter.