I need some help. I have a Verbatim External USB 3 drive that I am using for my time machine as well as storing video. I have successfully loaded many videos a while back, but now when I try to move more files there, it gives me an error message to say I don't have permission to access the files. I cannot recall ever setting up any permissions. I have updated my MacBook to the latest OS and wonder if this is part of the problem? I am not a very experienced OS user. so any help or suggestions on how to fix this issue would be appreicated