I'm running Window 8.1 Pro 64Bit, Intel i7 920, DDR3 6GB, GTX 260 SSE and currently running Dayz in compatibility mode. With Vanilla Dayz I was able connect to a server and play. After the current update v0.30.113899, I can launch and reach the game menu but the game crashes once I select play or change server.

Running at stock, I'll try your suggestions and report back

I'm running Window 8.1 Pro 64Bit, Intel i7 920 on ASUS P6T SE, DDR3 6GB, GTX 260 SSE and currently running Dayz in compatibility mode. With Vanilla Dayz I was able connect to a server and play. After the current updates I can launch and reach the game menu but the game crashes(ntdll) once I select "play" or "change server".

I've updated Windows, DirectX (what version of dx does dayz use), latest version of nvidia drivers and reinstalled Dayz.