Windows Adds Rich Thumbnail Preview for Files on Start Menu in Latest Insider Build 25921 for Canary Channel

Alongside recent Windows Insider Builds for the Dev and Beta Channel, Windows has released the latest build for the Canary Channel today. Sharing in a blog post, Windows announced the latest Insider Build 25921 for the Canary Channel including a slew of performance upgrades and features alongside bug fixes.

August 2023 Bug Bash: The August 2023 bug bash continues and runs through Monday August 7th at 11:59pm PDT. The bug bash will span the latest features available in the currently available preview builds across the Canary, Dev, and Beta Channels. Check Feedback Hub for quests!

JXR Background Support

JXR files may now be used as desktop backgrounds in Windows 11, and if you have an HDR monitor, they will render in full HDR.

First – make sure your device has an HDR display or is connected to an HDR display that supports HDR. You can check this by going to Settings > System > Display and checking the HDR toggle.

Next, download an HDR .JXR file to your device. Then right-click on your desktop, choose “Personalize” and then “Background”, and under “Personalize your background” – go and select the .JXR file you downloaded to your device.

You can download example .JXR files here to try this experience out on your HDR-capable device/display.

The background should load on your display. If you have multiple displays attached to your device, the background will show as HDR or SDR depending on each display’s capabilities. When using external displays attached to your device, we recommend running the HDR Calibration app for the best picture quality. Please note that for this build, there may be some issues with the HDR version of the desktop background not correctly display on some laptops with HDR.

Thumbnail Preview for Cloud Files

Windows now allows users with Azure Active Directory (AAD) accounts to preview files from the start menu. Previewing is currently limited to Microsoft Word documents, but support for additional formats is on the way. The functionality is activated by opening the start menu and hovering over the desired file, at which point a small box containing the file preview will appear. The feature will soon be made available to MSA users as well, Microsoft has confirmed. You can also use the right-click menu to quickly share the files with others.

File Preview | Windows

What will appear only for people logged with an AAD account currently are the richer thumbnail previews for cloud files if available such as Word documents. People who are logged in with an AAD account will see richer thumbnail previews for cloud files that look like this

When a user with a local account or an MSA hovers over files (including cloud and local files) under Recommended on the Start menu, they will see the following:

File Preview for MSA Users | Windows

NOTE: This feature previously rolled out to the Dev Channel with this flight and to the Beta Channel with this flight. We adjusted the text in both those blog posts based on feedback from Insiders.

Changes and Improvements


  • Cortana can be uninstalled in this build. For more on the end of support for Cortana, click here.

[Taskbar & System Tray]

  • Beginning to roll out with this build, Chat is now Microsoft Teams – Free. Microsoft Teams – Free is pinned by default to the taskbar and can be unpinned like other apps on the taskbar. Windows Insiders who click to launch Teams will discover a mini communications experience making it possible to chat, call, and meet with their people within just a click or two. Not only does its compact size make it easy to place the window anywhere on the desktop, but you can passively keep tabs on your conversations with the ability to have it visible as they browse the web or connect with your communities.  Phone Link integration is coming soon to Microsoft Teams (free) as well.
New mini communications experience in Microsoft Teams (free).
New mini communications experience in Microsoft Teams (free) | Windows

[Task View & Desktops]

  • When navigating between desktops in Task View (WIN + CTRL + left or right arrows), labels will be shown. New sliding animations will also show when you change your desktops using trackpad gestures, touch gestures, hotkeys and by clicking on the Task View flyout.
Labels will appear when switching between desktops.
Labels will appear when switching between desktops | Windows


  • A new asynchronous error-handling feature in the DHCP client service will allow for faster response time for some runs of ipconfig /renew on the Windows command line. Improvements will vary depending on system and network conditions, but ideal cases will improve from ~4.1 seconds to ~0.1 seconds per run.

Known issues

  • After updating to this build, devices with mobile broadband connectivity may not be able to connect to a wireless network due to an issue in which the APN configuration may get lost on the upgrade. You can either add in the APN configuration manually as a workaround or hold off taking this build as we expect to have the issue fixed in the next flight.

Farhan Ali

Farhan is a passionate writer with an undying love for games, PC hardware, and technology. With nearly 5 years of experience in blogging and over 14 years of experience in gaming, this is what he loves and does best.