I did a backup of my DCS.openbeta folder, launched the game and created a mission. It launched fine, but as soon as I did SHIFT-R (the restart mission keybind) the game crashed again.
Unticking "Full Screen" seems to have fixed the issues, but I'm losing a lot of FPS when not running in fullscreen
edit : I've set it back to Full Screen and it seems to still work, gonna do some more testing
edit 2 : negative, still crash when put back in full screen
edit 3 : ok, I messed with ticking and unticking full screen a couple of times (doing a restart each time), and now it's ticked and don't seem to crash anymore.
edit 4 : scratch edit 3
edit 5 : after playing a while on a MP server, just entering the mission edition make the game crash