If you cannot update from Windows 11 build 27686 to a newer release in the Canary Channel, do not worry; you are not alone. Microsoft has quietly revised the release notes for build 27695 to acknowledge the problem with its latest Canary builds not being able to upgrade due to a cryptic 0xC1900101 error and subsequent system rollback to the previous build.
Here is what Microsoft said in the update changelog for Windows 11 build 27695:
[ADDED 9/5] We’re investigating reports that starting with Build 27686, when upgrading to a newer Canary Channel build some Insiders experience a hang at the boot screen and their PC rolls back with error 0xC1900101.
The 0xC1900101 error joined two other known issues in the Canary build 27695. One affects Copilot+ PCs and breaks Windows Hello PIN and biometric authentication, and another bug abruptly closes the emoji panel when switching between emoji tabs or trying to select an emoji. Microsoft recently confirmed the problem with the emoji panel, and it is currently working on fixing it in future updates.
Windows 11 preview builds from the Insider program are not intended to run on mission-critical systems due to the high risks of significant bugs, and the confirmed issue with error 0xC1900101 is another reminder that using pre-release software on your main machine, especially from the Canary Channel, is not a very good idea.
In case you missed it, Microsoft introduced Windows 11 build 27695 on August 30, 2024. The build brought a new place for the Widgets button on the left-aligned taskbar, improvements to the Windows Local Administrator Password Solution (LAPS), a new "timebomb" for Canary builds, some tweaks for a better Windows Update experience, multiple bug fixes, and more.
You can check out the full release notes for Windows 11 build 27695 in our dedicated article.