Not new to mac. However, received new Mac Pro with two internal 1 tb hard drives. It is my second hard drive that I woke up to being locked and will not allow me to open it. I am the only user, the administrator, and I have done all the Command I permission stuff. When I do Command I on the drive, it says the under Sharing and Permissions that I have "Custom Access" which is the new part. I unlocked the lock and tried to change the name privelege to Read and write but the "Custom" does not change. I have run my system disk to see if I the hard drive is writeable and it says that it is. I cannot however run a permissions on this drive. THe drive checks out ok when I run disk first aid but that's it. No lock anywhere that I can find. THe icon of the hard drive by the way has a lock on it. Never had an issue like this before. THanks, for suggestions. George