I am developing a WinUI3 MSIX -based application. I have a valid code signing certificate that has signed the MSIX. When I double click the MSIX to install with App Installer, on the first screen it verifies the app as a Trusted App (see first attached screenshot). However, when I click the Install button, the installation fails with the error message "This app package is not supported for installation by App Installer because it uses certain restricted capabilities." (See the second attached screenshot) The install is being attempted on Windows 10 Enterprise 21H1 OS build 19043.1165.
Why won't the App Installer install this MSIX package? I thought the most recent Windows 10 release would install a properly signed MSIX without being denied for using so-called restricted capabilities.
Why does the first App Installer screen verify this package as a trusted app and indicate the package can be installed, only to abort the installation indicating that the package has not been verified?
To add more confusion, the MSIX installs successfully from PowerShell with the command
Add-AppxPackage -Path '.\TrustedAccess-WinUI3 (Package)_184.108.40.206_x64.msix'. Why does App Installer fail, while PowerShell