Files being corrupted when transferred

Hi Chris-l-381

Thank you for using the Apple Support Communities! Have you contacted the external dive manufacturer to check for any updates? We would also suggest the following resource that may help check the permissions:

Connect and use other storage devices with Mac

Hope this helps!

Have a great day.

Hi Chris-l-381,

Instead of transferring between two external drives, have you tried to transfer to your Mac first, then from your Mac to the other external drive? If you're having issues, transferring files this way may be a better option.

This section in the below article does show to go to and from the Mac:

Move files to or from an external storage device

• Make sure your Mac is connected to the external storage device (for example, using a USB cable or over a network).

• Click the Finder icon  in the Dock to open a Finder window, then do one of the following to move your files.

- Move files to the storage device: Select one or more files on the desktop or in a folder, then drag them to the storage device, listed below Locations in the Finder sidebar.

- Move files from the storage device: Select the storage device, listed below Locations in the Finder sidebar, then drag the files you want to a location on your Mac.

Connect and use other storage devices with Mac

Take care!