viralbug
Forerunner
one correction.. you need to start downloading and let it complete atleast 0.01 percent and then copy the files.. otherwise it will give the error.. this is because origin will start downloading by creating the bf3 folder which is necessary for this action..
I think I had done the same thing, but I forgot if I had started the download so didn't mention it. Had reinstalled my OS the other day so had to copy BF3 folder to avoid reinstalling the whole thing.
Origin really needs to have a backup feature.