Unable to Install .msix or .msixbundle Files in Windows 11

Hello, Kevin.Cowans

Welcome to the Microsoft community.

Thank you for your feedback. Regarding your issue of not being able to install .msix or .msixbundle files in Windows 11, here are some troubleshooting options:

Method 1:

Sometimes, the App Installer may need to be re-registered or repaired. This can be performed through PowerShell:

Search for PowerShell in the Start menu, right-click on it, and select “Run as administrator”.

Enter the following command to re-register the App Installer:

Get-AppxPackage *Microsoft.DesktopAppInstaller* | Foreach {Add-AppxPackage -DisableDevelopmentMode -Register “$($_.InstallLocation)\ AppXManifest.xml"}

Restart your computer and try installing the .msix or .msixbundle file again.

Method 2:

There may be a problem with the App Installer application itself, try fixing or resetting it:

Open Settings:

Press Win + I to open Settings.

Select Apps.

Then select Installed apps.

Find the App Installer and fix it:

Find App Installer in the list of apps, click on the three-dot menu on the right and select “Advanced Options”.

On the page that opens, select “Repair” and wait for it to complete.

If the repair doesn't work, try “Reset” again.

Method 3:

Make sure that Developer Mode is enabled, as this may affect the installation of .msix or .msixbundle files:

Press Win + I to open Settings.

Select Privacy & Security in the left menu.

Scroll down and select For developers.

Enable developer mode:

Toggle Developer Mode on.

Method 4:

If the above actions don't work, you can try to uninstall and reinstall the App Installer manually:

Search for PowerShell in the “Start” menu, right-click it, and select “Run as administrator”.

Uninstall the App Installer:

Get-AppxPackage *Microsoft.DesktopAppInstaller* | Remove-AppxPackage

Reinstall the App Installer:

Visit the Microsoft Store to download and install the App Installer.

Method 5:

Try an in-place upgrade

This will refresh your windows and will not delete your data, but for important data, it is still recommended that you back up.

How to run In-place upgrade in Windows 11 - Microsoft Community 

If none of the above methods work. it is more suitable for publishing on Microsoft Learn, more users post these issues there, you can click on "Ask a question", there are experts who can provide more professional solutions in that place.  

Here is a link to the forum where you can raise specific scenarios and share your idea to help solve the problem.  

I look forward to your feedback.

Best Regards,

Aaron| Microsoft Community Support Specialist