Can not start Minecraft Windows 10 after Update to 1.0.8

Hi,

after the auto-update to Version 1.0.8 (Skinpack Magic: The Gathering) I am unable to start Minecraft.

The "MOJANG"-Screen (red logon, black text on white, see attetchement) is shown, then, i drop back to the desktop without any further messages.

The last version worked flawlessly.

What can I do?