SOLUTION #1:
The fix will be in a future version of the launcher, but for now, you can edit Consolevariable.ini to change the console settings that may be the cause of the issue.
Go to: C:\Program Files\Unreal Engine\4.1\Engine\Config
Put this into Consolevariable.ini:
r.GraphicsAdapter = -2
SOLUTION #2:
If the first solution does not help, please download and follow the QFE instructions from here: