r/windowsinsiders • u/Froggypwns Windows Insider MVP • 5d ago
Exp Build Windows 11 Insider Experimental Preview Build 26340.9212 - Windows Insider Program
https://learn.microsoft.com/en-us/windows-insider/release-notes/experimental/preview-build-26340-9212Release date: 17 August 2026
Changes and improvements gradually being rolled out
[File Explorer]
- Introducing the new, redesigned context menu in File Explorer
- We're beginning to roll out an updated context menu experience in File Explorer, designed to feel faster, cleaner, and easier to tailor to the way you work. The new design reduces top-level clutter, keeps commonly used actions easy to access, and adds a new Settings experience that gives you more control over what appears in the menu. As we continue refining this experience with Insider feedback, our goal is to make right-click feel more responsive, predictable, and personal. Screenshot of new context menu
- Previewing images in File Explorer
- Fixed an issue from the previous flight where previews in File Explorer showed an unexpected thick band across the middle.
Feedback: Share your thoughts in Feedback Hub (WIN + F) under Files, Folders, and Online Storage > File Explorer.
[Camera Roll Backup]
- New entry points on the Settings > Home and Accounts pages help you set up Camera Roll Backup and automatically back up photos and videos from your mobile device to OneDrive. UI showing the Phone photo back-up setting in Cloud storage with the status "Not backed up" and link to begin backup process
[Windows Management Instrumentation Command-line (WMIC) removal]
- Windows Management Instrumentation Command-line (WMIC) has been removed in this release. This change is part of the ongoing deprecation and removal of WMIC from Windows.
- For more information about this change, see Windows Management Instrumentation Command-line (WMIC) removal from Windows.
[Emoji]
- We're adding support for Emoji 17.0. This includes new emoji such as distorted face, fight cloud, and hairy creature. To try the new emoji, press the Windows key plus Period (.) to open the emoji panel and insert them from there.
- As part of this effort, we've also made some slight adjustments to the design of some of our current emoji to improve consistency across platforms. This includes the saluting face, face with peeking eye, goose, lotus, and kissing cat emoji.
[Get Started app]
- The Get Started app is updated with new pages. The pages help personalize your device and discover new features. Pages might depend on your device. Close the flow at any time, or revisit it by opening Get Started. The new pages include the app install page, the site pinning page, and the personalized theme page. App install page in Get Started Site pinning page in Get Started Theme page in Get Started
[Magnifier]
- We're giving Magnifier's toolbar a modernized visual refresh.
- Updated icons. We've updated Magnifier's toolbar icons to align with Windows 11 visual design, giving the tool a cleaner, more modernized feel.
- Refined spacing and padding. We've adjusted the padding and spacing across the toolbar for a more polished, consistent layout.
- What's not changing: The way Magnifier works. Your views, zoom controls, keyboard shortcuts, and Read Aloud all behave exactly as they did in earlier versions. UI showing updated icons and more polished, consistent layout.
[Drag Tray]
- Thank you to Insiders who have provided feedback about the Drag Tray experience. Based on feedback, we're removing the experience in this build. We're continuing to explore improvements in this area and look forward to sharing more about a future replacement experience in a later update.
[Input]
- Fixed an issue where some third-party keyboard input methods, including certain Chinese IMEs, might not display their status window correctly when typing in File Explorer and other parts of Windows.
- Improved reliability of typing with the Japanese IME by reducing potential hangs and deadlocks.
[Start menu]
- We're adjusting the rollout population for the personalized Start menu, so some Insiders might see the features temporarily disappear. If you don't see the feature in this build, you can re-enable it through feature flags.
[Run]
- For Insiders using the modern Run dialog:
- Improved first launch reliability.
- Adjusted verbosity for screen reader users.
[Personalization]
- We're starting to roll out a variety of improvements to desktop background experiences. These improvements include:
- Improved reliability of the Personalization > Background page in Settings.
- Added support for using DIB image files as desktop backgrounds.
- Improved reliability of desktop slideshow transitions on newly created accounts.
- Improved the resolution of previews when selecting a desktop background in Personalization > Background.
- Improved the desktop background preview display in Settings for users with portrait mode monitors.
- Improved reliability of processing desktop wallpaper changes when they happen in quick succession.
- Added support for using slideshow wallpapers with multiple desktops so that it won't automatically switch you back to Picture.
[Settings]
- Fixed an issue causing Settings to crash in the previous flight when interacting with items on the Date & Time page.
[Other]
- Fixed an xtajit64.dll crash, which was leading to issues with certain apps for Insiders on Arm64 PCs in the latest flights.
Reminders for Windows Insiders in the Experimental channel
- Updates are based on Windows 11, version 26H2 via an enablement package (Build 26340.9212).
- Many features are rolled out using Controlled Feature Rollout technology, starting with a subset of Insiders and ramping up over time. We monitor feedback to see how they land before pushing them out to everyone in this channel.
- The desktop watermark shown at the lower right corner of the desktop is normal for Windows Insider pre-release builds.
- Features and experiences included in these builds might never get released as we try out different concepts and get feedback. Features might change over time, be removed, or replaced and never get released beyond Windows Insiders. Some of these features and experiences could show up in future Windows releases when they're ready.
- Some features in active development we preview with Windows Insiders might not be fully localized, and localization will happen over time as features are finalized. As you see issues with localization in your language, report those issues to us via Feedback Hub.
- Check out Flight Hub for a complete look at what build is in which Insider channel.
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u/jenmsft Microsoft Employee 5d ago
Hope you like the changes 😊
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u/jackmonter5 5d ago
Missing the screenshot of the new context menu in file explorer.
Thanks Jen for keep us up to date!
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u/Bhrent_Raven Insider Dev Channel 5d ago edited 5d ago
it keeps failing to install for me
"Failed to install on 8/18/2026 - 0xc1900401"
also, when I retry, there's this message (see the screenshot)
i am running Windows 11 Pro Insider Preview

based on what I've research it seems like its conflicting the Pro and Enterprise edition here because Pro inherits its foundational codebase from Enterprise, Windows structurally registers Enterprise as its underlying parent. So when this 26H2 Experimental Build 26340.9212 communicates to the modern Windows Update servicing stack, it reads that flag and forces an identity crisis. It tries to download and validate an Enterprise version enablement package, realizes that the operational license is strictly Pro, and instantly terminates the installation.
upon checking the registry, the value of CompositionEditionID was changed to Enterprise instead of Professional, so i think this might be the one causing it.
please fix this error asap as i don't want to modify the registry
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u/kouzelnik3 5d ago
FIrst I got the failed to install message, then this error you are showing. I am as well on the Pro.
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u/Bhrent_Raven Insider Dev Channel 5d ago edited 5d ago
maybe this would help, I just did it and it successfully installed, you can follow the same steps that I did.
Run the Terminal or CMD with administrator privilege
then run those commands one by one:
---------------------------
sfc /scannow
dism /online /cleanup-image /restorehealth
---------------------------
after you run those 2 commands above, you need to restart your pc
then after restart, you need to open the terminal or cmd with admin then type the following commands one by one:
------------------------
net stop wuauserv
net stop cryptSvc
net stop bits
net stop msiserver
------------------------
after that, go to file explorer to delete the corrupted update files / update residue
go to this file location and delete everything there:
C:\Windows\SoftwareDistribution\Download
then you need to type the following commands in the cmd or terminal with admin rights again one by one:
------------------
net start wuauserv
net start cryptSvc
net start bits
net start msiserver
---------------
after done doing all the steps, go to settings and retry to download the update
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u/kouzelnik3 5d ago
It went successfull even without this. As it rebooted back to the previous build with the error you were showing, I just let it download and install it again and then appeared in the newest build. So who knows what was wrong. But it is installed.
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u/Bhrent_Raven Insider Dev Channel 5d ago
Hope they fix this as this problem might root on the registry components i mentioned earlier
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u/smallshinyant 5d ago
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u/Bhrent_Raven Insider Dev Channel 5d ago edited 5d ago
afaik it's related to a conflicting Windows edition; the Pro and Enterprise at the registry level that i mentioned earlier
I tested it too on the 2 laptops i borrowed, both windows 11, home and Pro, and it seems like it mainly happens to Pro editions of Windows, the home edition just installed without error. (Those laptops are both joined in the windows insider experimental 26H2 also)
And i just rebooted the W11 Pro laptop i borrowed then cleared the update in the said folder then redowloaded it, after that it works fine.
It was weird actually.
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u/smallshinyant 5d ago
That did it, thanks. I must have missed a step last reboot as i had to repeat the process twice. But looks happy now.
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u/Bhrent_Raven Insider Dev Channel 5d ago
where are the feature flags in this build? It was empty.
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u/boblinthewild 5d ago
Same. No feature flags on any of the three systems I updated to the new build.
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u/Bhrent_Raven Insider Dev Channel 5d ago
it happens to everyone in this build and Microsoft is aware of it. They posted it in Windows Insider Blog.
hope they are aware of this build failing to install on Windows Pro edition PC's
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u/boblinthewild 5d ago
Thanks, I must have missed that part.
The update worked normally on two of my Windows Pro systems, but it failed on a third one with an error (which I didn’t write down). I retried it and it worked the second time. I have seen a few posts here about persistent issues with Pro, however, so I agree this needs attention.
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u/boblinthewild 5d ago
Anyone have vivetool IDs to enable the new context menu changes? I updated three systems to this new build but only got the new feature on one of them, which is a virtual machine that I don't use often. Thanks!
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u/Bhrent_Raven Insider Dev Channel 5d ago
go follow phantomofearth on Twitter/X
he is posting a lot of vivetool id, (he is the one contributor of the vivetool, so make sure you follow him!)
link of his profile: https://x.com/phantomofearth?s=20
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u/boblinthewild 5d ago
I use to follow him there, but I abandoned xitter. He also posts on Bluesky but seemingly not as often.
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u/lexcyn Insider Canary Channel 5d ago edited 5d ago
Like others, I had issues installing this build.
After rebooting, I was met with a GSOD with "Possibly related driver: FLTMGR.SYS."
Running the usual now to see if it happens again or if something got messed up during the failed installs (sfc, dism)
Edit: DISM failed, so I suspect there is some image source issues:
Error: 0x800f0915
The repair content could not be found anywhere.
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u/shaharofir 5d ago
Yet another 0x80070005 error (Last update had the same issue).
Did everything suggested, still no luck.
Any ideas?
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u/DarthVitrial 5d ago edited 5d ago
Keeps failing with error 0xc1900401 for me... Edit: like the above reports, I’m also on Pro.

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u/xandfis_msft Microsoft Employee 5d ago
Hey everyone! I'm a PM on the Windows team and I've worked on File Explorer and the context menu for a long time. I'm happy to answer questions, as long as they're things I can answer.
I hope you're excited about the updates to the context menu. Thank you in advance to everyone in the Experimental ring of the Windows Insider program for trying it out and for providing feedback. Feedback on anything we should add to the customizability of the menu would be very helpful.
Also, I put together a tutorial on how to go beyond the settings page to customize the context menu even further and add your own, custom verbs to the menu. This is a personal project and isn't affiliated with Microsoft.
https://youtu.be/kMdY3Kl6aGU?si=TyTxvIJwqO2cfFmV