I tried, getting the same thing as earlier (crash on startup). This is the log file:
22/05/2015 16:31:39:622 [05764] | INFO | Initializing Crosire's ReShade version '0.18.4.850' built on '2015-05-13 10:47:39' loaded from "E:\Steam\steamapps\common\The Witcher 3\bin\x64\dxgi.dll" to "E:\Steam\steamapps\common\The Witcher 3\bin\x64\witcher3.exe" ...
22/05/2015 16:31:39:641 [05764] | INFO | Registering hooks for "C:\Windows\system32\d3d8.dll" ...
22/05/2015 16:31:39:641 [05764] | INFO | > Delayed.
22/05/2015 16:31:39:641 [05764] | INFO | Registering hooks for "C:\Windows\system32\d3d9.dll" ...
22/05/2015 16:31:39:641 [05764] | INFO | > Libraries loaded.
22/05/2015 16:31:39:642 [05764] | INFO | > Found 9 match(es). Installing ...
22/05/2015 16:31:39:685 [05764] | INFO | > Installed 9 hook(s).
22/05/2015 16:31:39:685 [05764] | INFO | Registering hooks for "C:\Windows\system32\d3d10.dll" ...
22/05/2015 16:31:39:685 [05764] | INFO | > Delayed.
22/05/2015 16:31:39:685 [05764] | INFO | Registering hooks for "C:\Windows\system32\d3d10_1.dll" ...
22/05/2015 16:31:39:685 [05764] | INFO | > Delayed.
22/05/2015 16:31:39:685 [05764] | INFO | Registering hooks for "C:\Windows\system32\d3d11.dll" ...
22/05/2015 16:31:39:685 [05764] | INFO | > Libraries loaded.
22/05/2015 16:31:39:686 [05764] | INFO | > Found 2 match(es). Installing ...
22/05/2015 16:31:39:696 [05764] | INFO | > Installed 2 hook(s).
22/05/2015 16:31:39:696 [05764] | INFO | Registering hooks for "C:\Windows\system32\dxgi.dll" ...
22/05/2015 16:31:39:696 [05764] | INFO | > Delayed.
22/05/2015 16:31:39:696 [05764] | INFO | Registering hooks for "C:\Windows\system32\opengl32.dll" ...
22/05/2015 16:31:39:696 [05764] | INFO | > Delayed.
22/05/2015 16:31:39:696 [05764] | INFO | Registering hooks for "C:\Windows\system32\user32.dll" ...
22/05/2015 16:31:39:696 [05764] | INFO | > Libraries loaded.
22/05/2015 16:31:39:707 [05764] | INFO | > Found 4 match(es). Installing ...
22/05/2015 16:31:39:726 [05764] | INFO | > Installed 4 hook(s).
22/05/2015 16:31:39:726 [05764] | INFO | Registering hooks for "C:\Windows\system32\ws2_32.dll" ...
22/05/2015 16:31:39:726 [05764] | INFO | > Libraries loaded.
22/05/2015 16:31:39:728 [05764] | INFO | > Found 8 match(es). Installing ...
22/05/2015 16:31:39:766 [05764] | INFO | > Installed 8 hook(s).
22/05/2015 16:31:39:766 [05764] | INFO | Initialized.
22/05/2015 16:31:39:953 [05764] | INFO | Redirecting 'CreateDXGIFactory({7B7166EC-21C7-44AE-B21A-C9AE321AE369}, 000000000205E958)' ...
22/05/2015 16:31:39:953 [05764] | INFO | Installing delayed hooks for "C:\Windows\system32\dxgi.dll" ...
22/05/2015 16:31:39:954 [05764] | INFO | > Found 2 match(es). Installing ...
22/05/2015 16:31:39:954 [05764] | INFO | > Installed 2 hook(s).
22/05/2015 16:31:43:981 [05764] | INFO | Redirecting 'CreateDXGIFactory({7B7166EC-21C7-44AE-B21A-C9AE321AE369}, 000000000205F3D8)' ...
22/05/2015 16:31:43:998 [05764] | INFO | Redirecting 'RegisterClassExW(000000000205F3C0)' ...
22/05/2015 16:31:43:998 [05764] | INFO | > Adding 'CS_OWNDC' window class style flag to 'W2ViewportClass'.
22/05/2015 16:31:44:002 [05764] | INFO | Redirecting 'D3D11CreateDevice(0000000000000000, 1, 0000000000000000, 0, 0000000000000000, 0, 7, 0000000002057A50, 0000000002057A70, 0000000002057A58)' ...
22/05/2015 16:31:44:002 [05764] | INFO | > Passing on to 'D3D11CreateDeviceAndSwapChain':
22/05/2015 16:31:44:002 [05764] | INFO | Redirecting 'D3D11CreateDeviceAndSwapChain(0000000000000000, 1, 0000000000000000, 0, 0000000000000000, 0, 7, 0000000000000000, 0000000000000000, 0000000002057A50, 0000000002057A70, 0000000002057A58)' ...
22/05/2015 16:31:44:002 [05764] | INFO | Redirecting 'CreateDXGIFactory1({7B7166EC-21C7-44AE-B21A-C9AE321AE369}, 0000000002056D98)' ...
22/05/2015 16:31:44:213 [05764] | INFO | Redirecting 'IDXGIFactory::CreateSwapChain(00000000B7B2F080, 0000000074A97890, 000000000205F380, 000000000205F368)' ...
22/05/2015 16:31:44:217 [05764] | INFO | Recreated effect environment on runtime 00000000C5D30F90.
22/05/2015 16:31:44:217 [05764] | INFO | Redirecting 'IDXGISwapChain::SetFullscreenState(00000000C5AE7610, FALSE, 0000000000000000)' ...
22/05/2015 16:31:44:464 [03936] | INFO | Loading effect from "E:\Steam\steamapps\common\The Witcher 3\bin\x64\ReShade.fx" ...
22/05/2015 16:31:44:480 [05764] | INFO | Redirecting 'IDXGISwapChain::SetFullscreenState(00000000C5AE7610, TRUE, 00000000C643D3B0)' ...
22/05/2015 16:31:45:175 [05764] | INFO | Redirecting 'IDXGISwapChain::ResizeBuffers(00000000C5AE7610, 1, 1920, 1080, 28, 0x2)' ...
22/05/2015 16:31:45:219 [05764] | INFO | Recreated effect environment on runtime 00000000C5D30F90.
22/05/2015 16:31:45:346 [03936] | INFO | Loading effect from "E:\Steam\steamapps\common\The Witcher 3\bin\x64\ReShade.fx" ...
Don't worry if you're not sure, I can live without it but would be nice to play the game with sweetfx.