Hi, I do not know I am having the same problem. I saved some file by using disk utility and was able to open using the password that I set. But, once my mac crashed and got repaired, I had to recover all the files( including the dmg files) and stored it in DW passport. When I connect the Passport to Mac and tried to delete the dmg files, I was not able to. It says, this file cannot be deleted.Please help.....