I know this was a common error experienced by a lot of people, but did anyone ever get to the bottom of it. I have just had it for the first time. The EVO 4 had a similar problem and HTC moved quickly to release an update which seems to have solved it. I had heard that the bug could be caused by the auto-backup feature, so I had never used it. However, I recently turned auto-back up on and, low and behold, I get the error. A reboot fixes the problem and I have not had it again since, although I have turned auto-update off. Some people say auto-update messes up the permissions, others say the supplied cards are of a low quality and prone to corruption... but does anyone know for sure? Whilst the error is present, you cannot modify the contents of the card and cannot therefore take pictures etc.