Microsoft has already released Windows 10 Technical Preview build 9860 and one of the big questions was if the company was going to make available an ISO version of the latest build.
One of the major problems is that the preview of Windows 10 is not a final product, as such users are testing the operating system in many different way. The Microsoft’s Windows Insider program data on build 9860 shows that 41% of the installations are happening on desktops, 32% on laptops, 22% on virtual machines, while only 2% of the installations are happening on tablets, 1% on AllinOne, and the remaining 2% are from other types.
Perhaps one of the easiest and safest way to install Windows 10 is a VHD or VHDX, creating dual-boot system with current version of Windows. But users on these configuration are finding out that installing a new build on a virtual hard drive isn’t support. So having an ISO version of the preview will be ideal to create a new dual-boot system with the latest version of Windows 10.
However, according to Microsoft’s Gabe Aul, there won’t be an ISO download for Windows 10 Technical Preview 9860 and there is no indication that this will change in the future. Basically, every time you download the ISO file from the Windows Insider Program, you’ll get the original version the Windows Technical Preview build 9841 and then once the installation completes, you’ll have to update to the latest build to whatever it might be at that time.
— Gabriel Aul (@GabeAul) October 21, 2014
Update: But… Here is a workaround the issue: Windows 10: Creating custom ISO from any Technical Preview build.