First launch fails with "preparing to launch" message which closes and then then nothing happens.

[TigrisMorte]

Support did the usual, "your drivers and updates, uninstall then reinstall, verify cache,..." all to no avail. Finally they got to "Please uninstall both the x64 and x86 versions of 2015 vcredist". This of course also failed (and many of file names, the paths, and assumptions they made were wrong). However attempting to remove and install 'Visual C++ 2015 Redistributable' failed with "Cannot install a product when a newer version is installed.". So a quick google session later I discovered that 'Visual C++ 2015 Redistributable' has been replaced with 'Visual C++ 2017 Redistributable' (unlike previous versions it replaces the 2015 version).

So long story short, (too late!):
The Visual C++ 2017 Redistributable is a binary-compatible in-place upgrade of the Visual C++ 2015 Redistributable. Some poorly coded and tested programs fail on install or first run if the generated setup hard coded a C++ 2015 redistributable dependency and the 2017 C++ redist is installed.

Code Monkey fail:
The Total War launcher on first run incorrectly checks for 'Visual C++ 2015 Redistributable' and fails to recognize 'Visual C++ 2017 Redistributable' as a compatible replacement.

Solution:
Remove 'Visual C++ 2017 Redistributable' (both x86 and x64), install 'Visual C++ 2015 Redistributable' direct from MS (both x86 and x64), and tested the program. It started. I exited, installed 'Visual C++ 2017 Redistributable' direct from MS (both x86 and x64). Ignore the files in '\Program Files (x86)\Steam\steamapps\common\Total War WARHAMMER II\_CommonRedist' as they are not even the most recent version of 'Visual C++ 2015 Redistributable'

Hope this helps.

[Wh♂♂par]

Through a random click, I saw this and want to bump it, so that either other people see it, or the dev might reconsider implementation. :P