I had a 4TB Seagate external hard drive mounted on my Mac. It contains about 1TB of movies and photos, leaving 3TB of free space. My issue is when I try to add a folder of photos to the drive, the system won’t let me. When I right-click the drive icon and choose Get Info, I find a window that says “You can only read” under “Sharing & Permissions.” I’m not very computer savvy. Can somebody please help!
It’s obvious that your Seagate external hard drive is formatted with NTFS, a Windows format read-only on Mac.
It won’t let you write to it because you don’t have write access to it by default. To enable read/write support to NTFS on Mac, install iBoysoft NTFS for Mac.
This is the best NTFS driver for Mac I’ve used in recent years.
Hey, take a look at this post: Can’t Save/Write to External Hard Drive on Mac (7 Solutions).
It covers different scenarios where you may fail to write data to an external hard drive on Mac in details.