I was struggling to get some MKV files to play and I fixed it, after much fiddling, by removing the nonstandard characters from the file name. In this case the files had brackets in the name, which I removed, and afterwards the files played fine. OK, so there were audio sync issues, but that's another problem. The point is that one thing to try if you're getting "Data is corrupted" error is to use only letters, numbers, and underscore in the file names. Probably should remove spaces too.