I've been having this problem for about a month now but it could be longer than that (just noticed a month ago). When I try to start DCS it will not launch, either the VR version or non-VR.
The only thing that seems to work is deleting a couple of folders out of the game folder and repairing the game. I usually delete the API folder and the Bazar folder and re-install them. No, I cannot fix the game by just running DCS repair. It says it fixes something but the game will still not launch.
This seems to happen about every week or so whether I play the game or not. I just had to do this again and I just played on Saturday.
Does anyone have any suggestions? The only modification I've made to DCS is I installed some head-tracker binaries for Freetrack since I'm poor and don't have real TrackIR.