The game won't start

[mf ultimate ᓚᘏᗢ]

When I try to start the game, it just shows a black screen (if I'm running in fullscreen) or a white screen (if I'm running in windowed mode) and stays unresponsive until it's forced to close. This happens regardless of whather I run it from the configurator, directly from Steam, or from the .exe in the game folder.
I've read threads from people experiencing a similar issue, but the solutions that worked for them won't work for me.

So far I've tried:

• Running the game in fullscreen and windowed mode
  
• Running the game from the configurator, from Steam and from the game exe
  
• Resetting my card's settings to default ("Reset to factory defaults") from the Catalyst Control Center panel
  
• Tweaking various display settings (namely antialiasing, texture filtering/anisotropy, tessellation and vsync) from the Catalyst Control Center panel
  
  I'm running on:
  Windows 8.1 OEM 64-bit
  Intel i3-4150 @ 3.50GHz
  2*4GB Apotop RAM
  Sapphire Radeon R9 270X (4GB GDDR5)

[hottomo]

Same problem with a nvidia solved with anisotropic filtering and antialiasing set to application controled in the nvidia control panel.

[mf ultimate ᓚᘏᗢ]

I already said in the first post that I'd tried that.
But now, inexplicably, the game works without me having changed anything since my last test, so whatever.