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 later this year, and the second is from the 19H1 branch, which, as its name indicates, will arrive in the first half of next year.

It’s rare for the Windows Insider program to get two new builds on the same day (the last time was in March), but it’s certainly happening more often nowadays than in previous years. Microsoft is becoming more comfortable developing two updates of Windows 10 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 17723

This RS5 build introduces a mixed reality feature called Flashlight, which lets you peer into your physical environment without removing your headset. This build lets you see into the real world at any time via the Start menu, a button shortcut, or a voice command. The feature opens a low-latency pass-through camera feed connected to your controller.

Edge has received new Group Policies and MDM settings for IT administrators. On the flipside, Edge has lost the XSS filter, which Microsoft feels is no longer needed, thanks to modern standards like Content Security Policy. Edge also adopts Unicode 11 and its 157 new emoji.

This build also brings improvements to time itself. There’s new leap second support (keeps UTC in-sync with mean solar time), a precision time protocol (delivers far more accurate time samples to the endpoint), and software timestamping (eliminate the software delay introduced by the Windows networking stack).

There is now a simplified assigned access configuration page (Settings => search for “assigned access” => “Set up a kiosk”) that allows device administrators to easily set up their PC as a kiosk or digital sign. Furthermore, Edge now works with assigned access, allowing IT administrators to create a tailored browsing experience designed for kiosk devices: digital/interactive signage, public browsing, public browsing, and normal mode.

As for updates, Microsoft says it has trained a predictive model that can accurately determine when the right time to restart the device is. Windows 10 will not only check if you are currently using your device before restarting for an update, it will also try to predict whether you have just left the device for a few minutes.

As for gaming, Microsoft is making it easier to access the Game bar. You can now discover Game bar from the Start menu or bring up Game bar by using the Win + G shortcut at any time.

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

Fixed an issue resulting in the “…” menu not working in multiple apps (including Microsoft Store, Photos, and Screen Sketch) where clicking on any of the items would just make the menu dismiss.

Fixed an issue where in certain cases on PCs with multiple monitors, all the windows might have appeared shifted “up” and mouse input going to the wrong location.

Fixed an issue where SNMP and the Windows Event Log service might start using an unexpectedly high amount of CPU in the last flight.

Fixed the issue with Windows Defender Application Guard no longer working after installing the Build 17713.1002 Cumulative Update.

Fixed an issue from the last flight where upon rebooting in order to start upgrading to the build, the system would boot back into the current build rather than the new one.

Fixed an issue resulting in upgrades to the previous build failing with error 0x8007001f.

Fixed an issue from the previous flight where Window Recovery Environment (WinRE) would not launch and resulted in “Reset this PC” and “Advanced startup” flows to be broken and appear to do nothing.

Fixed an issue resulting in some laptops experiencing a CRITICAL PROCESS DIED bug check when the PC was put to sleep by closing lid and the connected power disconnected.

Fixed an issue resulting in ShellExperienceHost.exe crashing when trying to pin apps to Start Menu via drag and drop.

Fixed an explorer.exe crash when launching the Default Apps Settings page via WIN+R ‘control /name Microsoft.DefaultPrograms /page pageFileAssoc’.

Fixed an issue where .mkv files were using a generic app icon in File Explorer instead of a thumbnail.

Delivery Optimization Settings now has a new icon.

Fixed an issue where suggestions on the main page of Settings would appear after a delay, making the Settings categories shift unexpectedly.

Fixed an issue where Notification Settings listed every possible quick action in the enable/disable quick actions section, even those not applicable to the PC being used (including two Focus Assist entries).

Fixed an issue where the systray overflow area could end up drawing slightly below the taskbar.

Fixed an issue resulting in the network state in the taskbar potentially becoming stale in recent builds (showing there was no connection when there was, and vice versa).

Fixed an issue where pinging PCs by name on the same LAN would do a case-sensitive name check.

Fixed an issue where using v6v4tunnel to establish a tunnel didn’t work.

Fixed an issue in Command Prompt from the previous flight where if a typed string wrapped around to a second line, you could only delete it up to the line break.

Fixed an issue resulting in Task View / Timeline crashing on launch for some Insiders in recent builds.

Fixed an issue where right-clicking an activity in Timeline was missing the “clear all from day” option.

When you open a PDF using Microsoft Edge, the activity will now be listed in Timeline.

Fixed an issue where sometimes you would see windows unexpectedly quickly reorder after exiting Task View without selecting a window.

Fixed an issue from recent builds where the clock in the taskbar was leaking graphics device context handles (HDCs) every time it redrew, leading to performance issues the longer a PC was running. Multiple factors can impact performance, so if you’re continuing to notice any issues after upgrading to this build, please log feedback including a performance trace with a short repro and description.

Fixed an issue resulting in not being able to distinguish the border between two overlapping Command Prompt windows.

Reverted the welcome screen to the previous string “These updates will protect you in an online world.”

Tweaks to the design of the Cortana & Search landing page, specifically in situations where Cortana isn’t enabled/supported.

Fixed an issue resulting in Microsoft Jigsaw hanging on launch in recent builds.

The settings menu in Microsoft Edge (“…”) is now acrylic.

When you right-click a book in the Microsoft Edge Books pane, you’ll now see an option to share the book.

Fixed an issue that could result in Microsoft Edge spellchecking even though spellchecking was turned off in Settings.

Fixed an issue where using the mouse wheel in Microsoft Edge would unexpectedly do a forward/back through browser history if focus was in the address bar and “Scroll inactive windows” was disabled.

Fixed an issue where when using certain sites to listen to music in Microsoft Edge, your mouse might experience a small freeze if moving when the song changed.

Fixed an issue resulting in apps like Adobe XD crashing on keypress in recent flights.

Fixed an issue that could result in a deadlock on certain devices after using the pen to ink.

Fixed an issue where the touch keyboard would still have a launch animation even if “Show animations” was turned off in Ease of Access Settings.

Fixed an issue where launching regedit.exe (or any .exe that requires elevation) from a non-elevated cmd window using the “start” start command produced a “parameter is incorrect” error.

Fixed an issue causing Narrator speech to fade when waking from sleep mode.

Fixed an issue where the error “Your fingerprint couldn’t be recognized. Try using a different finger.” was displaying unexpected characters in place of the apostrophe.

In the RS5 branch, this update bumps the Windows 10 build number for PCs from 17713 (made available to testers on July 11) to build 17723.

This build has 14 known issues:

The clock & calendar flyout may not appear until bringing up Start or Action Center (and then they will both appear at the same time). This same issue may also result in notifications not appearing until Start or Action Center is opened.

You may see some unexpectedly light colors in these surfaces when in dark mode and/or dark on dark text.

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.

When you set up Microsoft Edge as your kiosk app and configure the start/new tab page URL from assigned access Settings, Microsoft Edge may not get launched with the configured URL. The fix for this issue should be included in the next flight.

On Build 17723 (but not Build 18204), you may see the notification count icon overlapping with the extension icon in the Microsoft Edge toolbar when an extension has unread notifications.

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. If that doesn’t work, you can try to install a version of Office not from the Store.

When the Narrator Quickstart launches, Scan Mode may not reliably be on by default. We recommend going through the Quickstart with Scan Mode on. To verify that Scan Mode is on, press Caps Lock + Space.

When using 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. This is something we are actively working on.

If the Narrator key is set to just Insert and you attempt to send a Narrator command from a braille display then these commands will not function. As long as the Caps Lock key is a part of the Narrator key mapping then braille functionality will work as designed.

There is a known issue in automatic dialog reading where the title of the dialog is being spoken more than once.

For more information about Narrator new keyboard layout and other known issues, please refer to (Intro to New Narrator Keyboard Layout doc).

There is an issue where the tops of apps in tablet mode being clipped (i.e. missing pixels).

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.

Windows 10 build 18204

This 19H1 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.

There is not much of a difference between these two builds, beyond their branch. The first build has an extra issue, as noted above, but that’s about it. Going forward, of course, the two will diverge as RS5 bugs are squashed and 19H1 gets new features.

Don’t install either build on your production machine.