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Create a Custom ISO for Windows 10: Part 1 of 6

By Kari the Finn, guest blogger for Ed Tittel, courtesy of

Note: this blog is Part 1 in a series of 6 parts on the topic of using Sysprep to craft a custom ISO for use in installing Windows 10, aimed at the upcoming Creator’s Update scheduled to become available in mid to late April. Your guest blogger for this series is Kari the Finn, well-known Windows Install expert at He’s the person who put tools together (ESD2ISO and UUP2ISO) that let savvy installers convert Windows OS download files into ISO images that may be used to create bootable installation optical media or USB Flash Drives. Here’s Part 1 of 6:

Installing Windows 10 Is Easy…

Installing Windows 10 is easy. All you have to do is download an ISO from Microsoft, burn it to a DVD or flash drive, use it to boot the PC, and you’re off! Some 15 to 30 minutes later you’ll have a clean, fresh Windows 10 installation. But before it’s ready for production use, quite a lot still needs doing. Software must be installed, desktop and Start must be personalized to meet your requirements, and so forth. Next, repeat this process for each of your PCs. Then, when a reinstall is needed, you must repeat that procedure!

I hate doing unnecessary work especially if I’m going to repeat it regularly. That’s why I do this a bit differently. First, I install Windows 10, customize it to my needs, install all the software I need, then capture that installation and use it to create an ISO. Using this customized ISO for my installation media, I need half an hour to clean install Windows 10 with all my software and personalization. When I want to change something in my ISO, to add or remove software, change personalization, or to update or upgrade Windows 10, I simply update the image and create a new ISO. It’s fast and easy to do. Better yet: the more I use it, the more time it saves me!

Getting Started with a Custom ISO

In this post I show how to do this. You need install media for your preferred Windows 10 edition and software, a technician machine (Microsoft’s term, not mine: it means a PC on which you can work to build OS images), and about 20 minutes longer than it would take to clean install Windows 10 and all your software one time.

As I mentioned, the machine used to prepare a Windows image is called a technician machine. Any spare PC will do for this role. But I prefer (and recommend) using a Hyper-V virtual machine. (Note: Hyper-V is not available in Windows 10 Home and Single Language editions, so that means you must use Windows 10 Pro, Education, or Enterprise on your host machine, the one that’s hosting Hyper-V virtual machines.)

The process of creating a custom ISO breaks down into five clearly distinct parts:

  1. Install Windows and prepare assets while installing
  2. Update and customize Windows, install software
  3. Generalize Windows image with Windows System Preparation Tool (Sysprep)
  4. Capture Windows image, create ISO
  5. Update / Change ISO

Apart from whatever software you pre-installed in your Windows image, no third party tools, apps or other software is needed. Everything is done using native Windows 10 and Microsoft tools. We’ll tackle this job, one step at a time in the five numbered sections that follow. Because of overall, length this will be broken across six blog posts, of which this, the introduction, is Part 1. Tune in for my next blog post wherein I’ll tackle Step 1: “Install Windows and prepare assets while installing.”

Links to All Series Parts (1-6)

Part 1: Introduction & Overview
Part 2: Install Windows and Prepare Assets
Part 3: Update and Customize Windows, Install Software
Part 4: Generalize Custom Windows Image with Sysprep
Part 5: Capture Custom Windows Image, Create ISO
Part 6: Update/Change Custom Windows ISO