OWC Mercury Pro LTO High-Speed Low-Cost Archiving User Guide
- October 30, 2023
- OWC
Table of Contents
OWC Mercury Pro LTO
Getting Started – Mac
Thank you for purchasing the Mercury Pro LTO Thunderbolt 3 LTO archival storage solution. To use your new Mercury Pro LTO system, you need to install a few pieces of software. If you need to download the software, please use the links below.
Mercury Pro LTO Drivers and Software
- ATTO SAS HBA Drivers – These drivers are required for your LTO unit to be used with your computer.
- LTFS Support and Diagnostic Tools – The LTFS tools are required by some third-party software applications like OWC ArGest Backup. Please check your software requirements to see if this tool is needed. The Diagnostic Tools are used to check the health of your LTO unit.
https://download.owc.com/lto/mac
Required – ATTO Express SAS HBA Drivers
The package within the “ATTO SAS Driver (Install First)” named
macos_kextesashba4* allows your Mac system to see and access the Mercury Pro
LTO tape drive properly. As a minimum, you must install this package for the
Mercury Pro LTO unit to be recognized. Installation may require a security
authorized step (dependent on your current system security settings) and will
require a system reboot.
NOTE: Catalina and later macOS users: Once the installation completes, do
not click the Restart button when presented. Instead, you should be prompted
to allow a system driver extension (kext) from ATTO.
Open Apple Menu -> System Preferences and select Security and Privacy.
Make sure that you are on the General tab and unlock the pane. Click the Allow
button that appears in the lower section of the pane. 
You will then be prompted to reboot your system – click the “Not Now” button
and close System Preferences. You will be taken back to the Installer window –
click the “Restart” button there to complete the installation. 
Checking the Status of the Driver Installation
Once the system has rebooted, hold down the OPT key, open the Apple menu and
select “System Information …”
Select the Thunderbolt/USB 4 option in the Navigation List.
The Mercury Pro LTO unit should be displayed as attached to one of your
Thunderbolt ports. 
Select the PCI option in the Navigation list You should see the ATTO
Expresses H1244 listed and the “Driver Installed field should read “Yes”. If
neither of these are correct, the driver did not get authorized properly and
you will need to return to the first step. 
Navigation list
The Tape drive will show up in the information pane as shown above. 
Optional – LTFS Support Packages
If you will be using a backup app that depends on LTFS support for operation,
the next installation will be the 2 packages in the LTFS Tools folder.
The packages should be installed in this order:
- ICUFramework
- macFUSE
- ltfssde
During the installation of these components, you will be prompted as in the
ExpressSAS kext above by the macOS gatekeeper to allow the MacFuSE extension
to be enabled in Security and Privacy System Preferences. Follow the steps as
outlined for the ATTO SAS driver above to enable the MacFuSE extension.
You will once again be required to reboot your system to enable this
extension.
Optional – Tape and ATTO Diagnostic Tools
For checking on the health of your Mercury Pro LTO tape device, you should not
depend on errors reported by your backup application. Instead, we have
provided the appropriate tape diagnostic tools in the Install Packages DMG –
in this case the IBM “ITDT” package.
Also included with the “ATTO SAS Drivers” folder in the ATTO Config Tool
package.
This package is used for troubleshooting the ATTO HBA and to under the HBA
firmware version. It is not required for normal operations of the Mercury Pro
LTO.