Making Metro Installation Possible in Windows 8.1

The installation of Windows Metro Apps from file (as opposed to Micorosoft Store), also called "sideloading" is designed by someone truly sadistic. Essentially, you need four items to do it, most operations necessary are only accessible from the command line... This text assumes you to be in a non-enterprise environment (not joined to the domain).

  1. Obviously you need the app itself (file extension appx). This file is created by Visual Studio if you know how to ask for it.
  2. A "signing certificate" is the certificate (.cer) file that is stored by the VS alongside the .appx file. You need to "install" this certificate by clicking on it. Note that the system is very particular about placing of the certificate, defaults will not work. Just two places will work, my favorite is  Computer (not User!)  Trusted Root store. Yes, this does expose you to all the nasty stuff, the security system will dutifully warn you that security-wise you are now hostage of the person who signed the certificate. All this just in order to install an app, the decision to go along this route was clearly made by a moron.
  3. PC enabled for sideloading. This is done by manually editing the registry (using, say,  regedit) and adding the key HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows\Appx\AllowAllTrustedApps = 1
  4. Windows development license for this PC. This is achieved by typing the following Powershell command with elevated privileges: Show-WindowsDeveloperLicenseRegistration

Now, installing the application is just a matter of typing into the Powershell: Add-AppxPackage <file>.appx

The insane design decisions don't stop here. Licenses frequently expire, making you to go through steps 2 and 4 again. On top of it, the message for the expired development licesnse is truly bizarre:  "This app can't open". And, if you are smart enough to look into the logs, the message will be even more cryptic: under Applications and Services Logs > Microsoft > Windows > Apps > ... the message will contain words about "Windows contract" with "Status: Modified".