OK, so this is getting frustrating! It's been two days since it's started crashing. When i click PLAY, it's show the black screen for a second and than straight to desktop. Doesnt' load the game. Everything was fine untill 2 days ago, and i don't know what caused it to crash. Some people fixed the issue by deleting some files from bin folder, but that doesn't work for me. Could anyone please help since GOG does nothing about it? Thanks.

Same problem here. Came back from vacation, Galaxy then installed latest update and DLCs and since then the game doesn't start anymore. A fix would be really nice or at least a workaround. As it is, I just can't play the game at all. Not what i hoped for.

exactly, not what i hoped for. i mean, if u play i pirate game, crashes are understandable, but if you pay for a game, at least you can expect is for it to work.

If it's because you're trying to run the game with any other external programs affecting the game, you could try backing up and deleting or renaming d3d11.dll and dxgi.dll from "The Witcher 3 Wild Hunt\bin\x64" folder.
If nothing changes, then feel free to put the backed up files back in their original folder.

I personally found it impossible to run the game with for example steam overlay enabled.

Credit goes to Firek from sticky thread: "Streaming/video capture applications currently not working on some systems"

Just thought I would post this as I had a similar problem. Up until a few days ago the game was working perfectly. Then all of a sudden I started getting a black screen when launching the game...could not "alt tab" nor "Ctrl alt del" out the black screen. Was forced to shut down my pc manually.

Tried everything and nothing worked. Decided to disable Comodo firewall then the game worked fine. Now playing the game with Comodo Firewall running in Game Mode with no issues.

If you have the same issue and you have Comodo Firewall run the game whilst Comodo is in Game Mode and see if that works.

The same exact thing has been happening to me since last night! whenever i click "Play" the screen goes dark, but then goes back to GOG Client and the "Play" button goes green again.

I've tried uninstalling and reinstalling the game. It worked, but it says that i couldn't play my last save without the new Patch/DLC. and so i updated/verified my game in GOG, and as soon as the DLC finished downloading, the game started to crash on startup again. I really hope a fix comes out soon.

For people looking for a solution it might be that the GOG overlay makes it crash it seems the Witcher has trouble with overlays as Raizo886 mentioned above.

It worked for me, I also said to start Witcher as an administration because I had a saving problem.