Mojang released Minecraft Bedrock Preview/Beta 1.21.120.23 this week, and while the build is light on new content, it packs a pair of fixes that Windows players have been clamoring for: .mcaddon file associations work again, and the game no longer locks up your mouse when you Alt+Tab away.
The update lands first in the Preview/Beta channel—the testing ground where changes are validated before a wider stable rollout. If you install this experimental build on Windows 10, Windows 11, Xbox, PlayStation, Android, or iOS, you’ll get early access to the fixes along with the inherent risks of pre-release software. Here’s exactly what changed, why it matters, and how to dive in without putting your worlds at risk.
A Targeted Bugfix Pass—No New Blocks, Just Smoother Play
The 1.21.120.23 Preview doesn’t introduce new mobs, biomes, or gameplay mechanics. Instead, it addresses a handful of annoying, reproducible bugs that have been tripping up players and add-on creators. The most impactful changes for Windows users are the restoration of double-click-to-install .mcaddon behavior and a cure for the input freeze that occurred when the game window lost focus. Previously, pressing the Windows key or tabbing out could seize the mouse cursor, forcing a restart. Now, Bedrock behaves like a well-mannered desktop citizen.
Other fixes in the build include:
- Copper Golem statues now correctly preserve their name after being placed and broken.
- Copper trapdoor recipes work as expected, eliminating a crafting inconsistency that could stall redstone builds.
- Small stability and performance improvements, particularly around input handling and rendering hitches.
These aren’t earth-shattering changes, but for anyone who installs add-ons on a Windows machine or frequently switches between apps, they make a tangible difference in daily use.
What It Means for You
The impact of this update depends on how you play Minecraft.
For Everyday Players on Windows
If you’ve ever downloaded a .mcaddon or .mcpack file only to have Windows fail to recognize it, the restoration of file associations is a quiet victory. You’ll once again be able to double-click an add-on file and have it automatically imported into Minecraft, rather than manually navigating through the game’s menus. The input-freeze fix is even more welcome: you can now Alt+Tab to check your web browser, Discord, or streaming software without worrying that your mouse will become unresponsive when you return. Both fixes nudge the Bedrock edition closer to parity with the Java edition’s desktop polish.
For Creators and Add-on Authors
Creators who depend on behavior packs and resource packs should test their existing content against this Preview build immediately. The restored Windows file associations streamline the installation loop during development—no more hunting for the right folder every time you re-export a pack. However, Preview builds can change internal APIs or entity behavior, so packs that relied on quirks from older versions might break. In this update, even a small tweak like the Copper Golem naming fix could affect maps or adventures that expected the old (buggy) naming behavior. Re-validate, re-export, and clearly document version compatibility for end users.
For Realm and Server Operators
Hosts need to be cautious. Once you upgrade a world to a Preview version, its data format may no longer be compatible with the stable release. Players on different channels cannot reliably play together—a Preview client joining a Realm running on stable Bedrock can trigger synchronization errors or corrupt shared data. If you’re managing a community, consider setting up a separate test instance and encourage users to submit bug reports rather than trying to run Preview builds on your main server.
How We Got Here
The .mcaddon file association regression was introduced in a prior Bedrock update, likely during a refactor of the Microsoft Store package. Players quickly noticed that double-clicking add-on files no longer triggered the Minecraft installer, and the workaround—dragging files into the resource_packs or behavior_packs folders—was tedious. The input freeze bug appeared around the same time, possibly related to how the game handles focus events when using controller, keyboard, and mouse simultaneously. Community feedback channels lit up with reports, and Mojang’s rapid response in this Preview build suggests they considered these issues high-priority for the Windows experience.
Copper-related bugs are another story. Since the 1.21 “Trails & Tales” update expanded copper mechanics, edge cases have emerged: the Copper Golem statue’s name tag inheritance was broken in certain conditions, and the trapdoor recipe sometimes returned the wrong result when crafted in bulk. These are the kinds of low-severity but high-annoyance bugs that erode trust in the game’s consistency. Their inclusion in this bugfix pass signals that Mojang is listening to community reports filed via the official feedback site.
What to Do Now
You have three paths forward: install the Preview safely and contribute to testing, wait for the final release, or gather information to make an informed choice. Here’s a practical workflow for each audience.
If You’re Installing the Preview
On Windows:
1. Choose your installation method. If you use the Minecraft Launcher, select “Minecraft: Bedrock Edition,” click the dropdown next to the Play button, and choose “Latest preview.” If you prefer the Microsoft Store, search for “Minecraft Preview” as a separate app and install it side-by-side with your stable version.
2. Back up your worlds before launching the Preview. Copy the folder %localappdata%\Packages\Microsoft.MinecraftUWP_8wekyb3d8bbwe\LocalState\games\com.mojang\minecraftWorlds to a safe location, or use the in-game export feature on your stable version.
3. Export any behavior or resource packs you care about. On Windows, they live in the development_behavior_packs and development_resource_packs folders inside the same com.mojang directory.
4. Launch the Preview and test intentionally: open a fresh creative world first, then carefully load a copy of a survival world. Do not use your main save until you’ve confirmed stability.
On other platforms: The installation steps differ—Xbox and PlayStation users download a separate Preview app; Android users enroll in the Beta via Google Play; iOS users join the TestFlight program. The same backup principle applies: export worlds and packs before you upgrade. On consoles, you can usually copy saves to an external drive or use Realms as a temporary backup.
If You’re Holding Off
That’s a valid choice. Wait for the stable release, which should arrive in the coming weeks once Mojang gathers enough Preview feedback. You won’t have to worry about world corruption or add-on breakage, and you’ll still get the same fixes eventually. If you’re in the middle of a long-term survival world or a build contest, staying on the stable channel is the safest move.
How to Roll Back If Something Goes Wrong
If the Preview introduces a problem—frequent crashes, broken add-ons, or world load failures—you can revert:
- Windows (Launcher): Change the dropdown from “Latest preview” back to “Latest release” and restart. Uninstall the Preview if you installed it as a separate app.
- Xbox/PlayStation: Uninstall the Preview and reinstall the main game from your library. Restore your worlds from the backup you made earlier.
- Android: Leave the Beta program through the Google Play Store page for Minecraft, then reinstall the app. You may need to restore worlds manually.
- iOS: Uninstall the TestFlight build and reinstall from the App Store when stable lands.
Always verify your backed-up worlds in the stable client before deleting anything. Once you’ve loaded a world in the Preview, its save data may have changed; your backup is your insurance policy.
Reporting Bugs That Matter
Preview builds live and die by community feedback. If you spot a bug, reproduce it in a minimal environment—a flat creative world with no add-ons—and capture the exact steps. Report it through the in-game feedback button or via bugs.mojang.com, including your platform, build number (1.21.120.23), and any logs. Good reports accelerate fixes for everyone.
For this build, pay particular attention to:
- Whether .mcaddon associations hold after multiple installations.
- Any lingering mouse or keyboard input oddities when minimizing or Alt+Tabbing.
- Copper recipe and statue behavior in worlds that were originally created in older versions.
Outlook
The 1.21.120.23 Preview is a maintenance stepping stone, not a destination. Its fixes are narrow but address real pain points, especially on Windows. Mojang’s willingness to ship a build that prioritizes file associations and input hygiene over flashy features should reassure players who want Bedrock to feel as stable on PC as the Java edition.
Keep an eye on the Preview notes page for a subsequent build that may incorporate feedback from this cycle. If all goes well, the fixes will graduate to the stable channel within a few weeks. Until then, play it smart: backup, test, report, and enjoy the satisfaction of a mouse cursor that doesn’t freeze every time you check your email.