FAQ - Frequently Asked Questions - Knowledge Base
[NT2 U3.1] Unable to access and copy files on Mac OS X 10.11
If you are unable to access the NT2 U3.1 on Mac OS X 10.11 (El Capitan) and copying files to the drive fails, please update the firmware of your NT2 U3.1.
For more information about the firmware update, go to Support > Firmware > NT2 U3.1 Firmware.