So the game actually works properly eventually, you would just like to not see that grey screen first, is that right?
Please attach here your Documents/Paradox Interactive/Europa Universalis IV/settings.txt and pdx_settings.txt .
From your Documents/Paradox Interactive/Europa Universalis IV/logs/ folder, attach here system.log , error.log .
**File Locations on Mac OS X**
The executable and DLC folder are in Users/USER/Library/Application Support/Steam/SteamApps/common/Europa Universalis IV/
To see it go to the Finder, hit command-shift-G (ie Go To) and type in ~/Library/ .
The user files (settings.txt, error logs, saved games, gfx, mods) are in /Users/USER/Documents/Paradox Interactive/Europa Universalis IV/ .
Also in Steam please click on Steam-Help-System Info, and paste everything there into a text file and attach that here.