The Installer has encountered an unexpected error

Some internet searches will turn up many hits since there are a few ways of running an msi installer as administrator on Win8. I would do it using an elevated command prompt like this:

  1. Swipe in from the right edge of the screen, and then tap Search. (If you’re using a mouse, point to the upper-right corner of the screen, move the mouse pointer down, and then click Search. Or just press the start button in your task bar.)

  2. Enter cmd in the search box, and then right-click or press and hold Command Prompt*.

  3. Select Run as administrator from the menu. Click ‘yes’ when prompted by UAC. Once the command prompt window opens make sure it says Administrator: Command Prompt in the title bar.

  4. Run the installer using the following commandline(NOTE: replace C:\EpicGamesLauncherInstaller.msi with the path to your installer. Don’t forget to include the .msi file extension.)

    msiexec /i C:\EpicGamesLauncherInstaller.msi