This is typically caused by anti-virus/firewall software preventing the game from writing save files on your computer. Please double-check your anti-virus and firewall settings, and ensure these have exceptions for the game.

If this does not resolve the issue, please find where the game is installed and right click on the WD4.exe file (it's most likely in a location like C:\Program Files\Epic Games\).

Choose Run as Administrator, then right click it again and select Properties. Click the Compatibility tab, and choose to run the game in Windows 8 compatibility mode. These steps should allow you to launch and play.