I can't install .Appx files anymore

Hi, I’m Cesare and I type from Bologna (Italy) and I have a PC with the Windows 10 Pro Insider Preview - Build 21322.rs_prerelease.210220-1651 version installed.

I made some changes to the system registry and now every time I want to launch an .Appx file, instead of opening and installing the application normally by clicking twice on it, an error window opens where I read “Interface not registered” with a Red X and obviously I can’t install .Appx programs.

How do you advise me to do?
I don’t know much about these things, maybe I should uninstall the application that manages the .Appx files with powershell and then re-install it, but I know little about these things, you should give me a detailed explanation, as long as you know how to fix the problem …

Thanks to all in advance.

Check if sideloading is enabled, head to Settings > Update & Security > For Developers. Ensure the setting here is set to either “Sideload apps” or “Developer mode”. If it’s set to “Windows Store apps”, you won’t be able to install .Appx or .AppxBundle software from outside the Windows Store

Microsoft added a new “App Installer” tool that allows you to install .Appx or .AppxBundle applications graphically.See if it’s still installed

You can also install .Appx packages with Powershell,command is; Add-AppxPackage -Path "C:\Path\to\File.Appx"

See if your Default Apps list is shows up correctly. Setting -> Apps -> Default Apps -> Reset or Set Default by app or Choose defaults apps by protocol

And as a rule of thumb,keep your apps,bios and drivers updated