So I installed the pre-load of OA, but then decided I'd like to install it to it's own folder (I assume it can find the arma2 content). So then I uninstall OA and re-install to another folder.
Then to waste a day so I stop thinking about OA, I go to work on my missions... but what is this? Oh nothing, besides the fact that MyDocuments/ArmA2/ folder seems to be empty now... which contained all my files for my missions.
I've lost about 20 hours of work, which is great. I didn't have backups because I didn't think OA would REMOVE stuff that was there before it was.
Just beware to any other mission makers out there, if you uninstall OA, it will whipe your arma2 missions folder.