Beta Test New Theme Features


07/11/20 Update below. This post was originally published on April 19th, 2018. It has been updated to reflect the latest version of Mach2 and the most current Windows 10 build.

Windows 10 builds, especially Insider builds, contain many hidden features used by Microsoft to test or developer new features that are not officially released yet. These hidden features, though, are not enabled by default and require a special method to activate them.

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This is where a tool called Mach2 comes into play that was released by Windows expert Rafael Rivera.

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When originally released, you had to compile the program and scan debug symbols to find new hidden features in Windows 10 builds.

You can now simply download the program and consult Rivera's GitHub repository for the latest features found in a newly released Windows 10 Insider build.

Beta test new theme features 2020Beta

According to Rafael, these hidden features are located in Feature Control, which 'is a system used to gate off new and unfinished features from production users in production code.'

Using Mach2, you can manage the Feature Store, a component of Feature Control, to find, disable, and enable features that are normally hidden from non-Microsoft users.

Below we will explain how you can download Mach2 and use it to enable hidden features in Windows 10 builds.

How to use Mach2 to find hidden features in Windows 10

Before we start, it should be noted that Rafael warned that enabling hidden development features could cause problems with your Windows 10 installation. Therefore, they should only be used on a system that you do not care what happens, such as a virtual machine with a saved snapshot.

To get started, download Mach2 from the program's release page. Once downloaded, extract the zip file and open a Windows 10 elevated command prompt.

At the command prompt, 'cd' into the folder where you extracted Mach2 and type 'mach2.exe -help' to see the program's instructions.

To see what features are currently enabled in Windows 10, enter the 'mach2 display' command. If you have not previously enabled or disabled any features, the listings will be empty.

If you have enabled/disabled features already, then those listed features will be displayed. As you can see below, the feature corresponding to ID 23615618 is enabled.

The feature ID '23615618' corresponds to the new theme-aware Start Menu that is being developed.


After a new Windows 10 Insider build is released, Rivera will create a text file that compares the available features in the newly released build with the previous one. He then hosts these files on his GitHub page so that you can see the new features that were added in this release.

These features commonly use internal Microsoft names that do not make it clear what they do, and you will need to experiment with them to learn more.

For example, in the latest Windows 10 Insider build 20161, Rivera lists various new features (in green) found in this build that you can test. One of these features is called 'LivePreviewForTabs' and has an ID of '25478404'.

Beta Test New Theme Features

This feature is a test of a new ALT+Tab change that shows Microsoft Edge tabs in the Windows task list.

Beta test new theme features list

To enable this feature, you would type 'mach2 enable 25175482' and press enter.

To disable a feature, we would use the 'mach2 disable 25175482' command.

When disabling or enabling features, you may need to reboot the computer to be fully enabled or disabled.

Now that you know how to find, display, enable and disable hidden features, it's time to start playing around and seeing what you can find.

Beta Test New Theme Features List

Below I have listed some of the features that I could activate in Windows 10 Insider build 20161 using Mach2.

Hidden Features in Windows 10 Insider Build 20161 (21H1?)

I briefly went through the list of features in build 20161 and found a few that can be enabled. It should be noted that hidden features can sometimes be fickle and not work all of the time.

The hidden features we found are listed below.

System Control Panel Redirect (RedirectSystemControlPanel - ID: 25175482)

Microsoft has started testing the removal of the System control panel on Windows 10 and instead redirecting users to a new modern About page.

Beta Test New Theme Features Examples

Theme-aware Start Menu (ThemeAwareAndFluentTiles - ID: 23615618)

New Windows 10 Start Menu tiles with colored backgrounds and hello to partially transparent theme-aware tiles that look so much nicer.

Microsoft Edge tabs in ALT+Tab (LivePreviewForTabs - ID: 25478404)

Microsoft is testing a change to the Windows 10 Alt+Tab feature so that it also shows open Microsoft Edge browser tabs.

Can you find any others?

Beta Test New Theme Features 2020

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