The game doesn't start, it gets an error, see pic below.
My system is win7-64 pro.

Try a repair and/or updating DirectX.

Same for me,

Repaired it 3 times, it always downloads 53 Mb but it doesn't change anything
Driver, DirectX are uptodate, tried just adding the missing dll..only to get a new error :)

Try conntacting GoG support?

Battlefleet Gothic Armada won't load for me either. It keeps returning a "XINPUT1_4.dll" error. Is there any way to fix this?

AGH HAHAHAHAHAHAHAHAHA

https://docs.microsoft.com/en-gb/windows/win32/xinput/xinput-versions?redirectedfrom=MSDN

Oh Noes it looks like you all will have to update to windows 10 LELELELELELELEL

But is says, the game will run under win7 -.-
So now what ?

Do you know where to find a list of all the required .dll files to make the game work on Win7?

Be sure to send in a ticket to GOG Support so they know the game isn't working on Win7.

I also have this problem, however the game doesn't launch at all, there is just a quick cursor loading without any response from the game. I am using Windows 7 Professional 64-bit.

Try searching google. I've found an article on Steam forum for different game explaing how to run it on W7 (xinput 1.4 was also required).

The problem with manually creating the XINPUT1_4.dll is that the game will return other errors for other dll files. So we need to know the plugin or SDK that has to be installed to make this work on Win7. It says in the PCGamingWiki the game should work in Win7.

I don't have a W7 to test it, but you can give it a try.

As it is a wrapper, it doesn't have to be registered in the system.

https://steamah.com/mafia-ii-definitive-edition-how-to-fix-missing-xinput1_4-dll/

Yeah I already tried that. The game then starts to complain about other missing DLL's. This is why we need the whole package SDK or whatever to fix this problem. This is not just a one file problem.