Microsoft today released a new Windows 10 preview for PCs with Cortana improvements and Windows Mixed Reality fixes. This build is from the RS4 branch, which represents the next Windows 10 update the company has yet to announce (but is expected to ship in April). There is no new build from the RS5 branch today, but the server-side Cortana improvements are rolling out there as well.

Windows 10 is a service, meaning it was built in a very different way from its predecessors so it can be regularly updated with not just fixes, but new features, too. Microsoft has released four major updates so far: November Update, Anniversary Update, Creators Update, and Fall Creators Update.

The main improvements in this build center around Microsoft’s virtual assistant Cortana. There’s a new server-powered profile page (Notebook section => click the button to the right of your name) where you can add and edit your favorite places. These let Cortana provide you with traffic updates for your daily commute and give you reminders when you arrive or leave your places. The profile will eventually extend to cover your Interests, Family, Accounts, and so on, Microsoft promised.

Cortana’s new Notebook design has also been rolled out to all markets and languages where the virtual assistant is supported. Several performance improvements have also been deployed that should make Notebook load faster. Default skills now come with a set of tips for questions you can ask, either by clicking the suggestion, typing it out yourself, or talking directly to Cortana.

Windows Mixed Reality has been causing a lot of problems in the last few builds, but Microsoft is almost done addressing all the bugs. This build fixes the issue where the inbox apps would fail to load inside of Windows Mixed Reality. Microsoft is still investigating some rare instances in which newly placed holograms appear empty and the shell may restart when switching between places.

This desktop build includes the following general bug fixes and improvements:

  • Fixed an issue where if you had your phone linked to your PC prior to upgrading, you’ll find it has become unlinked after upgrading.
  • Fixed an issue that could result in Microsoft Edge crashing when turning off certain extensions.
  • Fixed an issue where Narrator would crash when using scan mode to read dialogs in Microsoft Edge.
  • Fixed an issue resulting in the page up and page down keys not working when using Microsoft Edge in Reading View.
  • Fixed an issue resulting in focus being lost after using WIN+A to close the Action Center.
  • Fixed an issue where if you switched your formatting to Japanese without having the Japanese language in your language list, newly installed apps wouldn’t appear in Start.

Today’s update bumps the Windows 10 build number for the RS4 branch from 17123 (made available to testers on March 16) to build 17127.

This build has no known issues, aside from the Windows Mixed Reality bug mentioned above. As always, don’t install this on your production machine.