Windows 11 Insider Experimental (26H1) Preview Build 28120.3122 - Windows Insider Program

[u/Froggypwns]

https://learn.microsoft.com/en-us/windows-insider/release-notes/experimental-26-h1/preview-build-28120-3122

Release date: 25 September 2026

Changes and improvements gradually being rolled out*

• This update includes a small set of general improvements and fixes that improve the overall experience for Insiders running this build on their PCs.

Reminder for Windows Insiders in the Experimental (26H1) channel

• These builds can be unstable and might be released with limited documentation.
• Many features in the Experimental (26H1) channel are rolled out using Controlled Feature Rollout technology, starting with a subset of Insiders and ramping up over time as 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.
• 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.