Workaround:
Navigate to the location where the .appinstaller file was downloaded.
Right-click the file and select Open with > App Installer to start the installation process.

Notes:
This error occurs when the downloaded .appinstaller file is not opened with the App Installer application when you double click.
To avoid installation errors in the future, you can configure App Installer as the default app for opening .appinstaller files.
To configure the App Installer as the default option:
Right-click on the downloaded file and select Properties.
Under the General tab > Open with, click Change.
Select App Installer and set it as the default app.