The Windows IMaging format (WIM) is a compression format created by Microsoft for usage in its Windows Operating System. WIM, first used in Windows Vista, is an optical disc image compression format which performs similar function as the ISO format.
The difference between both formats, however, is that the WIM format was designed to work with Windows system. In essence, it is more like a subset of ISO, just that it is more efficient for Windows OS. However, it is possible to create an ISO image file which contains the files inside a WIM, as an ISO image is more portable and it allows for diverse operations such as loading it on a virtual machine.
While you can find many software online which will help convert your WIM image into an Iso image, your best bet is to use the Windows Automated Installation Kit (Windows AIK).
How to Convert WIM to ISO
1. The pioneer step is to download the Windows Automated Installation Kit (Windows AIK) from Microsoft website (1.77GB). in the process of downloading this file, move the WIM file format you want to convert into an ISO image towards the root directory of your computer (normally “c:/”). You can choose to rename the WIM file for ease of conversion (in this case, we choose to name it “win10.wim”). in addition, install the Windows Automated Installation by using the prompt from the installation wizard.
2. As administrator, open the Deployment Tools Command Prompt. Open the newly installed application folder by navigating to the start menu and choosing Microsoft Windows AIK. Inside the folder, choose “Command Prompt”.
3. Inside the selected command prompt, open a Windows Preinstallation Environment (Windows PE) by typing “CopyPE C:Winpe” to set up the preinstallation environment. Afterwards, copy the WIM file which we named win10.wim to the PE by typing “Copy /y c:win10.wim c:WinpeISOSources”.
4. Go back to that PETools file folder by typing “Cd C:Program FilesWindows AIKToolsPETools”.
5. Afterwards, type “Oscdimg -n -bc:winpeISObootetfsboot.com c:winpeISO c:.iso” in order to generate an ISO image file from the PE. Voila! Your WIM file has been converted into an ISO Image.
6. Note that if the WIM file has to be turned into an ISO image is larger than a standard CD memory space of 700 MB, then type “Oscdimg -m -bc:winpeISObootetfsboot.com c:winpeISO c:winpe.iso” instead of the 5th step.
No doubt, conversion of .wim to .iso is somewhat stressful. However, except you are running a basic machine or some other esoteric activities, you are way better creating a bootable USB drive using the .wim file via Rufus.