If you have an external drive that you use with your Mac, and provided it is in a format that your Mac can read, then you by default should be able to access all of the files on it. However, there may be times when you are either barred from opening or accessing files or folders, or performing actions like deleting files may result in errors.

These error can include simple confirmation requests such as “Are you sure you want to delete the item“, or be full barriers that state you do not have permissions to delete the item. Either way, these can be a frustration when attempting to manage files on your drives.

May 26, 2020  Being a multiuser operating system, macOS sets up access permissions for all files and folders on the system, including external drives. Solution: Change permissions on Seagate external hard drive To fix the read-only Seagate external hard drive issue, you need to regain full access. I need to find out how to set the permissions of a USB flash drive at the device (not filesystem) level. In other words, I need to grant the user read/write access to a USB device identified by diskutil which is /dev/diskX where X is some integer. For example, I insert a USB flash drive and according to diskutil it's identifier is /dev/disk5.

This issue happens because of filesystem permissions being enabled on an external drive, which are rules on a per-file and per-folder basis that grant access to specified users and groups. Permissions are generally reserved to set up security and privacy on permanent local volumes, but since external hard drives can be used as permanent local storage (consider a RAID array for managing a large data store), then permissions can also be set up on them.

To fix this problem, you just need to have OS X ignore permissions on the drive again, which can be done with the following steps:

1. Locate your drive in the Finder by pressing Shift-Command-C and then selecting it.
2. Press Command-i on the selected drive to get information on it.
3. Click the lock and authenticate to make changes.
4. Locate the checkbox to “Ignore ownership on this volume” and check it.

After authenticating, ensure this box is checked to ignore ownership on a volume you have mounted. This will only be available on drives that support permissions.

When done, you should be able to copy any file to and from the drive. Note that this will apply for all users of your system, so everyone using your Mac should now be able to access all files on the drive. In addition, note that if you have multiple drives then this will need to be done for each drive separately, as there is no central setting to ignore permissions on all attached volumes.

Keep in mind that filesystem permissions only apply to volume formats that support them, such as NTFS and Apple’s Mac OS Extended; however, quite often external drives are shipped formatted with FAT32, which does not support permissions, and therefore should not be affected by permissions problems. In this case, you will not see an available option to ignore permissions on the drive when you get information on it.

Mac Os X Change Permissions Usb Driver

In the event that you are seeing these errors and warnings persist regardless of the status of the “Ignore Ownership” setting, then your drive’s formatting may be damaged and in need of repair. To check this, you can use Disk Utility or another drive management tool to verify and repair both the partition tables and formatting of the drive, and then try reading it again.

Download Mac Os To Usb

As a final note, since this issue has to do with filesystem permissions, you might be wondering about the Repair Permissions option in Disk Utility that is so prevalently recommended when troubleshooting problems in OS X; however, this only checks the permissions for files on your boot drive, and will not affect anything on an external drive.

Change Permission Usb Drive