Yeah, I tried that as well, but neither my Steam client nor normal client have a version.dat file so it crashes when attempting to run "Prevent File Re-check" -- does yours have a version.dat??
I also tried the recommended trick of replacing the pad00000 file, but that also always guarantees a redownload of files, and the game will not launch if you replace it after the version check from the launcher.
EDIT: After deleting the .meta.backup and files in the patch_temp dir I was able to finally get it working again.