I just noticed that your post has never received a reply, that's a shame. Mine has not received any either. I'm new to this community and I'm not a computer or programming guru. However, I have done the same thing that you've mentioned in your post many times and haven't discovered any problems with the data on the HDD. I attribute this to two possibilities. 1st, the data transferring has stopped due to the freeze and hard resetting woud be similar to unplugging it at that time, safe. 2nd, I don't believe that data is constantly moving from the HDD to the Wii while playing games anyway. Game boards or levels and other info is randomly loaded into RAM at the necessary intervals and not constantly, therefore you're not really playing directly from the HDD storage file per say. So when you encounter a freeze don't panic, the data transferring has stopped and data loss is really an issue only when data is being written into and for storage purposes and there is a connection failure of some type, otherwise what was successfully stored at one time has remained stored. Word to the wise, get another HDD, make a backup of everything in your first HDD and put it in a safe place. Away from the kids! I know it's late, but if my assumptions have been correct I hope it brings piece of mind for your future endevors.