I do apologize for kinda flooding the forum with topics as i already have an existing one where i mentioned DCS freezing for no reason at start up but now finally i have clearly identified what's causing the issue. After trying dozens of different things and playing around with windows settings, it turns out to be the TrackIR software that's causing this mess. Whenever i launch DCS without Trackir running, it just all works normally otherwise it freezes on main menu. Tried uninstalling software and reverting back to 5.4.2 still same happening.
Would be happy to hear any proven solutions for this