MDF and MDS are a pair of files that describe a disc image together. The MDF file holds the image data, and the MDS file holds the track and session information that describes how that data is organised. WinBin2Iso can convert MDF to ISO, which is useful when you want a single file that Windows can mount, but a plain ISO may not preserve everything the MDS described. For a straightforward data disc, conversion is usually fine. For a complex disc, keep the original pair.
WinBin2Iso is a free Windows tool by Nenad Hrg and SoftwareOK, latest v6.79 from 19 October 2026, distributed as ZIP files only with no installer. You can get it from the WinBin2Iso download page. This guide explains what MDF and MDS each do, how conversion works, and how to decide whether to convert, keep, or do both.
What the MDF file holds
The MDF file is the bulk of the image. It holds the disc data in a raw-ish form, similar in spirit to a BIN file, though in its own layout. If you only have the MDF file, you have the data, but you may be missing the organisational information that tells a tool how the disc was structured. That is why MDF files are normally distributed with MDS files, and why you should treat a lone MDF with a little caution until you know what disc it came from.
For a data disc, the contents of the MDF are what you ultimately care about: the files and folders that were on the disc. Conversion to ISO extracts that data into a single-file image that Windows 10 and 11 can mount natively. The conversion does not need to invent data. It repackages the data you already have into a more convenient form. If the MDF is incomplete or damaged, however, the ISO will reflect that, so checking the result matters.
What the MDS file holds
The MDS file is the small companion file, in the style associated with Alcohol 120%. It holds track and session information: how tracks are laid out, where sessions begin and end, and other structural details that the raw data alone does not spell out. Think of the MDS as the disc’s table of contents and structural notes, while the MDF is the disc’s contents.
How conversion to ISO works
WinBin2Iso converts MDF to ISO by reading the MDF data and writing it as a single-file ISO image. For a data disc, the result is an ISO you can mount in Windows, copy as one file, and store more easily than a pair of files. Our tutorial on how to convert MDF to ISO walks through the steps, and the general comparison in BIN vs ISO vs CUE vs IMG vs MDF puts MDF in context with the other formats.
Conversion is not the same as preservation of every detail. A plain ISO is a simpler structure than an MDF plus MDS pair. It is designed to hold disc contents in a standard, widely supported form, not to record every nuance of the original disc’s sessions and structure. For a single-session data disc, that simplification costs you nothing you were likely to use. For a multi-session or otherwise unusual disc, it can cost you structural information that only the original pair preserves.
What can be lost in conversion
The honest answer is: session and protection-related information, and other details that live in the MDS rather than in the user data, may not survive a conversion to a plain ISO. That does not mean files will disappear from a normal data disc. It means that if the original disc relied on session structure, or on details recorded in the MDS, to behave in a particular way, the ISO may not reproduce that behaviour exactly.
This is a reason to test, not a reason to panic. Convert, mount the ISO, and check that the files and folders you expect are present and readable. If they are, and the disc was a data disc, the conversion has done its job. If something looks missing or wrong, go back to the original pair rather than trying to repair the ISO. The original is your fallback, and it is far easier to reconvert than to reconstruct lost structure.
When to keep the original pair
Keep the original MDF and MDS pair when the disc is complex, when you are unsure what the disc contains, when you may need the original structure later, or when the disc is the only copy you have. Disk space is cheap compared with the cost of losing the only faithful copy of a disc. A sensible workflow is to convert to ISO for everyday use, verify the ISO, and then archive the original pair rather than deleting it immediately.
Keep the pair as your primary copy when the disc is an audio disc or a mixed disc with audio tracks, because track structure matters there in the same way it does for BIN and CUE audio discs. Converting a multi-track audio image to a single ISO can lose track boundaries, so the original pair is the safer master copy. For audio, see audio CD BIN to ISO and missing tracks, which explains the same caution in the BIN context.
Frequently asked questions
Do I need the MDS file to convert MDF to ISO?
WinBin2Iso converts the MDF data. The MDS is valuable for preserving the original structure and for tools that read the pair, so keep it even when the converter does not ask for it.
Will my files disappear if I convert MDF to ISO?
For a normal data disc, no. The files in the image should appear in the ISO. What may not survive is session and structural detail recorded in the MDS, which matters more for complex discs than for simple data discs.