Last Updated on May 7, 2026
When it comes to installing an operating system on your computer such as Windows 11, you usually need to either buy a copy of Windows on a flash drive, create your own flash drive using the Windows Media Creation tool or download an ISO file and create your own flash drive using a tool such as Rufus, Ventoy, or even the AnyBurn CD burning app.
If you are ok with installing Windows using all the default settings and options, that is fine. But if you want to customize the way Windows is installed and configured, there is a way to do that as well. In this article, we will be showing you how to create a custom auto unattended file and inject it into a custom Windows ISO file.
Creating your Custom Auto Unattended File
1. Access the Unattended File Generator
To successfully create our custom auto unattended file, we will be using an incredibly helpful online form that generates the script for us. You can easily access this generator tool by visiting the website linked here. Once the page loads, you will be presented with a massive list of customization choices that dictate exactly how your Windows installation will behave from start to finish.
2. Choose Your Configuration Options
There are many configuration options to choose from to make the operating system uniquely yours. You can customize settings such as disk configuration, your computer name, automatically adding user accounts, and proactively removing pesky Microsoft apps. You can also adjust personalization settings, bypass strict Windows 11 hardware requirements, tweak taskbar configuration, disable visual effects, handle Wi-Fi setup, and much more.
3. Configure and Download the XML File
For our specific example, we will configure the tool to install Windows 11 Pro and add a local user named Bob with a display name of Bobby. We will also set the start menu to be on the left of the screen, force the desktop background color to be orange, and automatically remove some Microsoft bloatware apps. Once you configure your desired settings, click the button that says Download .xml file and save your autounattend.xml file safely on your PC because you will need it for the next step
Creating your Custom Windows ISO File with your autounattend.xml File
4. Change the PowerShell Execution Policy
Now that we have our autounattend.xml file successfully created, we will now use it to create our custom Windows ISO image file with all the custom settings it contains. The first thing you will need to do is change the system’s script execution policy to allow all scripts to run without any restrictions. When you set the policy to unrestricted, it enables the execution of any PowerShell script, regardless of its origin or whether it is digitally signed.
5. Run the Unrestricted Command
To safely make this change, we need to open the Windows PowerShell utility as an administrator. Once the blue terminal window is open, you will need to run the following command: Set-ExecutionPolicy Unrestricted. The system will prompt you for confirmation, so simply type in the letter A for “Yes to All” and hit enter. You may also be able to get away with typing just the letter Y if you want to try that option first.
6. Launch the WIMUtil ISO Builder Tool
Now we will absolutely need to run another PowerShell script as an administrator to officially launch the WIMUtil ISO builder tool. You can find more detailed information about this specific tool here. Simply paste the command:
irm “https://github.com/memstechtips/WIMUtil/raw/main/src/WIMUtil.ps1” | iex
Into PowerShell and hit enter to download and run the utility.
7. Select Your Base Windows ISO
This command will quickly open the WIMUtil tool on your screen, and we can now start to create our custom ISO file. You will first need to select your base Windows ISO file by clicking the button and browsing for it on your computer. If you do not already have one downloaded, you can also seamlessly download a fresh one using the WIMUtil tool itself.
8. Choose a Working Directory
Right below the ISO selection, you will need to establish a working folder for the software to use. The Select Directory button is used to purposefully choose a temporary location where WIMUtil will keep its working files during the building process. You can confidently choose any folder on your computer for this step, as long as the drive has plenty of free storage space.
9. Add Your Custom Answer File
The next step in the tool is where we will finally add our newly created answer file that we made in the previous web generator step. The Download UW button can be used to load a preconfigured autounattend.xml file if you prefer not to make one. However, we will be loading our own custom file for this step by clicking on the Select File button and browsing to the exact location of our downloaded autounattend.xml file.
10. Extract Hardware Drivers (Optional)
Moving down the list, the Add Drivers step is an optional area where you can dynamically extract hardware drivers from the current computer you are using. If you are running the WINUtil tool on a specific machine, you can pull its drivers to seamlessly inject into your new ISO file. This feature comes in incredibly handy if you plan on immediately reinstalling Windows on the exact same computer you created the custom ISO file on.
11. Download the Oscdimg Utility
The final step involves downloading a small utility called oscdimg to be installed on your system. Oscdimg is a reliable command line tool strictly used to create ISO image files, and it is officially part of the Windows Assessment and Deployment Kit (ADK). Simply click the button to grab the tool, and then you can thoughtfully select a final save location for the finished ISO file to be placed at after it has been created.
12. Create the Custom ISO
Once everything is configured and your paths are set, you can go ahead and click the Create ISO button at the bottom. You will then clearly see the build progress scrolling rapidly in the background PowerShell window. This automated compilation step should only take a couple of minutes to complete, depending on the overall speed of your hard drive and processor.
Installing Windows with the Custom ISO File
13. Boot Your Computer with the Flash Drive
Now that our completely custom autounattend ISO file has been created, we can now confidently use it to install Windows from scratch. Once you make a bootable flash drive using Rufus or a similar tool, you can boot your computer directly from it. This will immediately bypass your old operating system and officially start the automated installation procedure.
14. Observe the Automated Setup Process
If you have ever installed Windows before using a standard retail ISO file, you will quickly notice that this custom process will look significantly different. The visual experience will also vary wildly depending on exactly how many things you customized for your personal autounattend.xml file. For our custom ISO, the very first thing it does after we press any key to boot from the image is run some specialized terminal commands entirely in the background.
15. Bypass the Initial Configuration Screens
Since we proactively chose which version of Windows to install and preconfigured our hard drive formatting settings in the very first step, the installation skips the usual boring prompts. It goes right to the “We’re getting a few things ready” screen without asking for a license key or drive selection. The system then quickly starts copying files and installing Windows without requiring any direct input from the user whatsoever.
Then it starts installing Windows without any input from the user.
16. Allow Windows to Configure Updates and Profiles
Once the initial heavy installation is fully complete, Windows will then automatically check for system updates just like it does when installing Windows the regular, tedious way. After checking for updates, it goes right into the first-time user profile configuration screen like you would normally see when logging in with a brand new user account. Since we cleverly configured a user account and password inside our autounattend.xml file, it simply logs it in for us without stopping.
17. Enjoy Your Customized Desktop
When the desktop finally loads, you will immediately see all of the specific visual changes you requested. In our example, we now have our custom orange desktop wallpaper prominently displayed on the monitor. We also have the standard start button and menu pushed over to the left side of the taskbar, exactly just like we configured in the web generator.
18. Verify Your Account and Computer Name
If you dig into your system settings, we can then verify the computer name we assigned back in the first step was successfully applied. You will also clearly see the local admin account that was automatically created and logged in without us ever touching the keyboard. Everything is completely set up and ready for immediate daily use.
19. Use UWScript for Further Customization
If you want to take things even further, you can visit the GitHub page where you can find more information about this entire process. There is also another powerful script called UWScript that you can easily download and run on your new computer, as well as on other computers that already have Windows installed on them. You can creatively use this tool to further debloat your system and profoundly tweak your Windows settings for maximum customization.
For additional training resources, check out our online IT training courses.
Check out our extensive IT book series.
