Microsoft today released a new preview for PCs with dark theme support in File Explorer and improvements to Narrator. This build is from the RS5 branch, which represents the Windows 10 update the company plans to release later this year. The company is also releasing builds from the 19H1 branch, which, as its name indicates, will arrive in the first half of next year.

Windows 10 is being developed as a service, meaning it receives new features on a regular basis. Microsoft has released five major updates so far: November Update, Anniversary Update, Creators Update, Fall Creators Update, and April 2018 Update.

Back in May, Microsoft released the first Windows 10 build to support a dark theme in File Explorer. Today’s build completes “what we set out to do for this release,” the team announced. That doesn’t mean dark theme development is done, but it does mean that what you see in File Explorer in this build is what you’ll get in the next Windows 10 release.

This desktop build also includes the following general bug fixes and improvements (most of which are for Narrator):

  • The XAML shadows have been taken offline and acrylic has been removed from some popup controls. They will be back in a later build.
  • Fixed an issue from recently flights where the touch keyboard might become invisible on the screen.
  • Fixed an issue in recent flights where components of a notification with a progress bar (like the one when using nearby sharing) might flash every time the progress bar updated.
  • Fixed an issue where on certain devices if you reset your device and chose to keep files, after logging back into Windows the Sound Settings page would be unresponsive.
  • Fixed the issue where the High Contrast dropdown flashed when the values were changed.
  • Fixed the issue where Narrator couldn’t access all the emoji in the Touch Keyboard’s emoji panel.
  • Fixed the issue where Narrator didn’t say “selected” after image was selected using the keyboard.
  • Fixed the issue where Touch Narrator’s focus remained on the word even after deselecting it.
  • Fixed the issue where the Narrator key got sticky when using the Mouse Mode command.
  • Fixed the issue where Narrator’s Command Restore Default dialog was not read by Narrator.
  • Fixed the issue where Narrator’s copy and paste feature would say “selection removed” but the selection remained.
  • Fixed the issue where Narrator automatic dialog read the Command key Assignment dialog twice.
  • Improved the Narrator experience when moving by character and announcing phonetic pronunciations.
  • Fixed the issue where Narrator focus and keyboard focus got out of sync after navigating TreeView controls.
  • Fixed the issue where Narrator misread the Calculator app’s display on focus for values over 100.
  • Fixed the issue where when launching Narrator QuickStart using the link in Narrator Settings, the Narrator icon would appear in the taskbar.
  • Fixed the issue where Narrator couldn’t read the label of the Word document recovery dialog.
  • Fixed the issue so Narrator can now navigate the New Notepad Status Bar contents.
  • Fixed the issue where Narrator Scan mode navigation didn’t progress after tabbing onto a link.
  • Fixed the issue where Narrator navigated out of the Microsoft Edge browser window using Scan mode on some web pages.
  • Fixed the issue where Narrator crashed when Developer Mode was in use and the generated string to display was null.
  • Fixed the issue where Narrator continuous reading got stuck on a table element in some HTML emails.

Today’s update bumps the Windows 10 build number for the RS5 branch from 17730 (made available to testers on August 3) to build 17733.

This build has 11 known issues:

  • Your PC will bugcheck (GSOD) when deleting a local folder that is synced to OneDrive.
  • Clicking a link to launch one app from another app may not work for some Insiders.
  • When you upgrade to this build you’ll find that the taskbar flyouts (network, volume, etc) no longer have an acrylic background.
  • When you use the Ease of Access Make Text bigger setting, you might see text clipping issues, or find that text is not increasing in size everywhere.
  • On Windows 10 in S Mode, launching Office in the Store may fail to launch with an error about a .dll not being designed to run on Windows. The error message is that a .dll “is either not designed to run on Windows or it contains an error. Try installing the program again…” Some people have been able to work around this by uninstalling and reinstalling Office from the Store.
  • When using Narrator Scan mode you may experience multiple stops for a single control. An example of this is if you have an image that is also a link.
  • When using Narrator Scan mode Shift + Selection commands in Microsoft Edge, the text does not get selected properly.
  • A potential increase in Start reliability and performance issues in this build.
  • After setting up a Windows Mixed Reality headset for the first time on this build with motion controllers, the controllers may need to be re-paired a second time before appearing in the headset.
  • When using a Windows Mixed Reality immersive app, saying “Flashlight on,” may fail to activate the flashlight feature even though the status appears as active on the Start menu.
  • If you install any of the recent builds from the Fast ring and switch to the Slow ring – optional content such as enabling developer mode will fail. You will have to remain in the Fast ring to add/install/enable optional content. This is because optional content will only install on builds approved for specific rings.

As always, don’t install this on your production machine.