What is a .wim file?
Windows Imaging Format File · Disk image · Microsoft · 2007 (Windows Vista)
A .wim file is a Windows Imaging Format archive: a file-based disk image Microsoft uses to deploy Windows itself. The install.wim on installation media contains the entire operating system.
What is a .wim file used for?
WIM images are file-based rather than sector-based, so one archive can hold several Windows editions while storing every duplicate file once. Tools like DISM apply, mount and service them, and Windows Setup installs from them directly.
IT departments meet WIM constantly: capturing golden images, injecting drivers and updates offline, and building bootable media. 7-Zip opens a .wim like a folder, which makes extracting single files easy.
How to open a .wim file
The .wim format opens in the following apps, grouped by operating system. If one app does not work, try another from the same list. For a step-by-step walkthrough, see how to open a .wim file.
Windows
- DISM (mount/apply)
- 7-Zip
- Windows Setup
macOS
- 7-Zip via CLI ports
- wimlib
Linux
- wimlib (wimlib-imagex)
- 7-Zip
How to convert a .wim file
You can convert a .wim file to esd (compress), iso (rebuild media), vhd (apply to virtual disk) using a conversion tool or the export menu of an app that opens it.
.wim file signature (magic bytes)
Programs recognise a .wim file by the bytes at the start of the file, not by its name. These are the signatures for WIM. For a full breakdown, see the WIM file signature page.
| Hex signature | Offset | Note |
|---|---|---|
| 4D 53 57 49 4D 00 00 00 | 0 | ASCII MSWIM |
See the full magic-numbers reference for every format.
Frequently asked questions
What is a .wim file?
A .wim file is a Windows Imaging Format archive: a file-based disk image Microsoft uses to deploy Windows itself. The install.wim on installation media contains the entire operating system.
How do I open a .wim file?
For a quick look, open it in 7-Zip. To work with it properly, mount it with DISM (dism /Mount-Wim) or wimlib, edit, then commit or discard the changes.
What is install.wim?
The core image on Windows installation media: it holds the complete OS, often multiple editions in one file. Setup applies it to your disk during installation.
How do I convert install.esd to install.wim?
Use DISM: dism /Export-Image with the source .esd, the index you want, and /Compress:max writes a standard .wim that deployment tools accept.
Related formats
Sources
Details on this page were checked against authoritative references: