Sorry, I didn't get a notification that this thread was updated. I don't run Citrix or RivaTuner. I see exactly what the OP sees, a completely blank window the size of the desktop, and Alt+F4 won't close it, it either says it isn't responding or I have to Ctrl+Alt+Del and end the task.

My graphics drivers are the latest version, although there were security patches that I downloaded. It did not help. I also tried closing all other programs apart from GOG and Windows processes and then running it, and disabling Aero, to no effect.

I'm on Windows 7 if that is important. I just checked the log file and that seems not to be there.

So I changed loads of things and it still doesn't work but it got further, and got a green bar at 89% with gurgling sounds, but the gurgling just repeated itself over and over until I killed the process. I'm going to try to isolate what single change made some progress and get back to you.

Edit: OK, so I'm very confused. I whitelisted the directory on Windows Defender (I had already closed my firewall) and ran as admin, and I got past the blank screen to the Brotherhood splash and progress bar. I then removed the whitelist and admin privileges and it continues to get past the screen, so now the configuration is exactly as before but now it gets further.

It still doesn't work through the GOG launcher but only via desolation.exe. If I add -force-d3d9 to the command linme the green progress bar gets to 100% rather than 89%, but it still hangs anyway.

And to make matters weirder, after trying unsuccessfully to run it via the GOG launcher, I now cannot run it directly through the executable either. It could be some config file is being updated each launch and overwriting good settings or something? And then the second time I ran it it started working again!

Still haven't got past 100% progress bar and gurgling sounds though.

Edit 2: OK, I think I know the problem. If I'm running GOG Galaxy the last lines of the log file are

[GOG GALAXY] Successfully signed in
[GOG GALAXY] Requesting Stats and Achievements
[GOG GALAXY] Checking LoggedOn status...
[GOG GALAXY] User logged on: True

If I run desolation.exe directly whiler GOG Galaxy is running I get the same log file. If I don't have GOG Galaxy running when I run desolation.exe, the game gets further, hangs at 100% progress bar, and now the last line of the log file is

[GOG GALAXY] Failed to sign in for reason FAILURE_REASON_GALAXY_SERVICE_NOT_SIGNED_IN

So, I'm downloading the offline installation files from the GOG website, will install it separately from GOG Galaxy, and see if that works. If it does, it's a clash between the game and GOG Galaxy that is the problem.

And... no. Now it stops at random points on the progress bar (69, 81, 89, 100), and once the bar finished and disappeared, but each time it still hangs.

So I installed this game this morning and all I got was a black window at the start. After trying different solutions from this thread I kind of gave up and then basically on my way out I tried "verify installation". And that fixed it!
Hmmmm...