Windows 10 build 17623

Windows 10 build 17623 releases with new features

A new test preview of Windows 10 (version 1809), part of the Redstone 5 development is now available with a new image file format, external GPU feature, changes to the privacy settings, and more. Here's all you need to know.

Microsoft is now making available Windows 10 build 17623 for PCs enrolled in the Fast ring using the Skip Ahead option. This is the third preview, part of the Redstone 5 development, and it introduces a number of new features and changes.

Windows 10 Insider Preview build 17623, similar to build 17123, introduces the High Efficiency Image File Format (HEIF), a safe remove experience for external GPUs connected using Thunderbolt 3, and add the new privacy settings layout in the set up experience you’ll find with Spring Creators Update. In addition, Windows Defender Application Guard (WDAG) gets a couple of improvements, and more.

What’s new on Windows 10 build 17623

Here are all the changes Microsoft is rolling out with this new Redstone 5 preview:

High Efficiency Image File Format (HEIF)

Starting with build 17623, Windows 10 now includes support the High Efficiency Image File Format, which is an image container that uses modern codecs like HEVC to improve quality, compression, and capabilities compared to earlier formats like JPEG, GIF, and PNG.

Also, this new format supports encoding image sequences, image collections, auxiliary images like alpha or depth maps, live images, video, audio, and HDR for improved contrast.  

You can try this new format in the latest version of the Photos app. Additionally, any application that uses WIC, WinRT Imaging APIs, or the XAML Image control can now add similar support for viewing single HEIF images. Just bear in mind that you’re only getting the essential viewing support, currently it’s not possible to edit HEIF images.


This new preview of Windows 10 version 1809 also introduces a safe remove experience for external GPUs connected via Thunderbolt 3.

The new experience allows you to know which apps are currently running on the external graphics processor to safely close them to prevent data loss as you disconnect the device.

In order to safely remove an external graphics card, open the “Safely Remove Hardware and Eject Media” icon, and click to eject your card. If you see any running app in the list, close them before detaching the GPU.


Similar to the changes found in the Redstone 4 development, Microsoft is now introducing an updated privacy experience to help users make the right privacy choices and offers two new settings for Inking & Typing and Find my device during the upgrade process.

Windows Defender

Windows Defender Application Guard for Microsoft Edge introduces a few new changes, including performance improvements, and now it’s possible to download files from a WDAG session, but this option must be enable manually, and it’s only available for users running the Enterprise version of Windows 10. (These changes are also included in the Spring Creators Update build 17120.)

Additional changes

Alongside all the new improvements, on build 17623, Microsoft is currently testing a change where links clicked on within the Mail app will open in Microsoft Edge.

Microsoft is listing the complete set of improvements, fixes, and known issues for Windows 10 Insider Preview build 17623 at the Windows Blog. In case you missed it, you can read all the changes for Windows 10 build 17620 in this article

Download Windows 10 build 17623

Although there are no ISO files for Windows 10 build 17623, the update is available immediately through the Fast ring with the Skip Ahead option for PCs. This preview build will download and install automatically on your device, but you can always force the update from Settings > Update & security > Windows Update and clicking the Check for updates button.

You can also check out these resources:

About the author

Mauro Huculak is a Windows How-To Expert who started Pureinfotech in 2010 as an independent online publication. He has also been a Windows Central contributor for nearly a decade. Mauro has over 14 years of experience writing comprehensive guides and creating professional videos about Windows and software, including Android and Linux. Before becoming a technology writer, he was an IT administrator for seven years. In total, Mauro has over 20 years of combined experience in technology. Throughout his career, he achieved different professional certifications from Microsoft (MSCA), Cisco (CCNP), VMware (VCP), and CompTIA (A+ and Network+), and he has been recognized as a Microsoft MVP for many years. You can follow him on X (Twitter), YouTube, LinkedIn and Email him at [email protected].