I want to just troll you can blame Win10, but there is a reason and a fix.
I would check this out:
http://www.dependencywalker.com/
I actually had help from the Marvel Heroes tech team years back, most game with a launcher will auto-select 32 or 64 bit based on your system's compatibility, if for whatever reason the 64-bit one fails to start it will default to 32-bit. The link is to a dependency checker, basically identifies and displays all files/DLL's that are needed to run the selected program. This was extremely useful to me in fixing my inability to run 64-bit clients at all, while not realizing there was in issue until I tried playing a game that had separate 32-bit and 64-bit clients for download and the 64-bit one would not load up and just crash.
Basically run the program from the link that matches your system (x64 one) and select the dx11 client from the game folder to test and any results that show up in red text are the culprits. The most common reason for these fatal errors is the x64 version is either missing or corrupted, this can be caused by OS updates, DX updates from installing other programs (where in a 64-bit client was added later and the devs never updated the DX version included) and malware/viruses.
To Fix: Delete the culprit DLL files completely, then go to the Microsoft website and download and install their latest comprehensive DX update. (This will take some time to run, as it will check and add any missing ones, complete deletion is required to break the associations so they can be properly replaced.)