Here are the fixes, improvements, and known issues in Windows 10 for PCs build 16170

Right on the heels of the release of the Windows 10 Creators Update for those that want to install it manually, Microsoft has released the first Redstone 3 build for PCs in the Fast ring. The build doesn't contain any new front-facing features just yet; instead, it focuses on improvements to OneCore, to make it "optimally structured for teams to start checking in code."

This is normal for the first Fast ring build that follows a feature update, and we'll likely get some cool new features beginning next month. There are, however, a number of fixes, improvements, and known issues. Here's what got fixed and improved:

We fixed the issue causing your PC to fail to install new builds on reboot with the error 8024a112.

We have updated the share icon in File Explorer (in the Share tab) to match our new share iconography.

We fixed an issue where Cortana Reminders was displayed as a possible share target when Cortana wasn’t enabled.

We fixed an issue where Miracast sessions would disconnect a minute or so after the Connect UI was closed if the connection was a first time pairing.

We fixed a high-DPI issue when “System (Enhanced)” scaling is enabled so as to now correctly display certain applications that use display graphics accelerated contents.

Turning the night light schedule off in Settings now turns night light off immediately.

Here are the known issues:

Narrator will not work on this build. If you require Narrator to work, you should move to the Slow ring until we get this bug fixed.

Some Insiders have reported seeing this error “Some updates were cancelled. We’ll keep trying in case new updates become available” in Windows Update. See this forum post for more details.

Some apps and games may crash due to a misconfiguration of advertising ID that happened in a prior build. Specifically, this issue affects new user accounts that were created on Build 15031. The misconfiguration can continue to persist after upgrading to later builds. The ACL on the registry key incorrectly denies access to the user and you can delete the following registry key to get out of this state: HKCU\Software\Microsoft\Windows\CurrentVersion\AdvertisingInfo.

There is a bug where if you need to restart your PC due to a pending update like with the latest Surface firmware updates, the restart reminder dialog doesn’t pop up. You should check Settings > Update & security > Windows Update to see if a restart is required.

Certain hardware configurations may cause the broadcast live review window in the Game bar to flash Green while you are Broadcasting. This does not affect the quality of your broadcast and is only visible to the Broadcaster. Make sure you have the latest graphics drivers.

Double-clicking on the Windows Defender icon in the notification area does not open Windows Defender. Right-clicking on the icon and choosing open will open Windows Defender.

Surface 3 devices fail to update to new builds if a SD memory card is inserted. The updated drivers for the Surface 3 that fix this issue have not yet been published to Windows Update.

Pressing F12 to open the Developer Tools in Microsoft Edge while F12 is open and focused may not return focus to the tab F12 is opened against, and vice-versa.

The Action Center may get into a state where dismissing one notification unexpectedly dismisses multiple. If this happens, please try rebooting your device.

It's worth noting that if you're thinking about whether or not you should install build 16170, there's virtually no gain that justifies the risk that's found in the known issues. Even if none of these are deal-breakers for you, the next build might have an issue that is.

We're likely to find out more about what's coming in Redstone 3 at Microsoft's Build 2017 developer conference next month. Once Microsoft makes some formal announcements about what we can expect, we'll probably start seeing those features in Insider builds.

If you're on the Fast ring, you can grab today's build by heading over to Settings -> Update & security -> Windows Update -> Check for updates. If not, go to the Windows Insider Program tab and click 'Get started'.