Microsoft today released two new Windows 10 previews for PCs. The first build is from the RS5 branch, which represents the Windows 10 update the company plans to release next month, and the second is from the 19H1 branch, which, as its name indicates, will arrive in the first half of next year.

This year, Microsoft has released two new builds on the same day more frequently than ever before (the last time was in July). The company is simply more comfortable developing two major Windows 10 updates at once.

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.

Windows 10 build 17763

This RS5 build includes the following general bug fixes and improvements:

  • The build watermark at the lower right-hand corner of the desktop is no longer present in this build.
  • Fixed an issue where touching a Flash element in Microsoft Edge with two or more fingers could result in the tab crashing.
  • Fixed an issue where thumbnails and icons might not be rendered if there were any video files saved to the desktop.
  • Fixed an issue where certain Bluetooth audio devices wouldn’t play sound in apps that also used the microphone.
  • Fixed an issue resulting in an unexpectedly increased use of battery recently when using certain apps like OneNote.
  • Fixed an issue in PowerShell where it wasn’t displaying characters correctly in Japanese.
  • Fixed an issue resulting in display scaling factors not being applied correctly (so the UI was smaller than expected) when viewing a full screen remote desktop window on a monitor set to certain display scalings.

In the RS5 branch, this update bumps the Windows 10 build number for PCs from 17760 (made available to testers on September 14) to build 17763.

This build has two known issues:

  • Task Manager is not reporting accurate CPU usage.
  • Arrows to expand “Background processes” in Task Manager are blinking constantly and weirdly.

Windows 10 build 18242

This build is for Windows Insiders who have chosen the Skip Ahead option, meaning they continue to receive builds from the RS_PRERELEASE branch. Only a small subset of Insiders can opt into Skip Ahead, as Microsoft still needs testers helping with RS5.

This 19H1 build includes the following general bug fixes and improvements:

  • Fixed an issue resulting in the background of notifications and the Action Center losing color and becoming transparent in the last two flights.
  • Fixed an issue where thumbnails and icons might not be rendered if there were any video files saved to the desktop.
  • Fixed an issue resulting in the back button in Settings and other apps becoming white text on a white background if you hovered over it.
  • Fixed an issue resulting in certain apps crashing when you tried to save a file from the app.
  • Fixed an issue resulting in nearby sharing not working for local accounts where the account name contained certain Chinese, Japanese, or Korean characters.
  • Fixed an issue resulting in rendering issues in certain types of PDFs in Microsoft Edge.
  • The Emoji Panel is now draggable if you would like to move it to a different position.
  • Fixed an issue resulting in Narrator not reading selected word choices when typing using an IME (for example, in Japanese).
  • Some Insiders who have opted in to Skip Ahead may notice differences when using the Japanese IME in today’s build.
  • Fixed an issue where certain Bluetooth audio devices wouldn’t play sound in apps that also used the microphone.
  • Fixed an issue resulting in slower resume from hibernation on certain devices in the last few flights.
  • Fixed an issue resulting in Windows Hello spending more time in the “Getting Ready” state in recent builds.
  • Fixed an issue resulting in an unexpectedly increased use of battery recently when using certain apps like OneNote.
  • Fixed an issue in PowerShell where it wasn’t displaying characters correctly in Japanese.

In the 19H1 branch, this update bumps the Windows 10 build number for PCs from 18237 (made available to testers on September 12) to build 18242.

This build has three known issues:

  • Task Manager is not reporting accurate CPU usage.
  • Arrows to expand “Background processes” in Task Manager are blinking constantly and weirdly.
  • 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.

Don’t install either build on your production machine.