I have an external hard drive set up for backing up with Time Machine on my Mac. It has been working well. Now when time machine tries to back up it tells me the external disk is read only. The hard drive does mount to the computer and will let me open the Time Machine folder. When I am in disk utility it also sees the external hard drive but will not let me click on repair disk permissions. Under the drive info’s sharing & permissions window it said ” You can only read.” , After unlocking everything is grayed out, but the permission is set to read & write. Any thoughts on how to get this drive back to read and write? Its a 2TB drive with 1.79TB on disk. The drive has not been ever used on a windows machine or use on any other computer and is use only for Time Machine backups. One day it was read/write next day read only. Thanks!