I have an LTO tape drive with a built-in ATTO Thunderlink SH 1068 that relies on an end-of-life(EOL) ATTO SAS/HBA kernel extension, the ATTO ThunderLink SAS HBA Driver 1.25.

Upon upgrading to macOS Sierra, the kernel extension won't load, so the LTO tape drive doesn't show up in the SAS device tree. It was working fine on El Capitan 10.11.6.

It seems that Gatekeeper in Sierra is now blocking this kernel extension.

Running kextutil -t in Terminal as a diagnostic reveals that the code signature is invalid:

MacBook-Pro:~ user$ sudo kextutil -t /Library/Extensions/ATTOThunderLinkSASHBA.kext 
Diagnostics for /Library/Extensions/ATTOThunderLinkSASHBA.kext:
Code Signing Failure: code signature is invalid
Untrusted kexts are not allowed
ERROR: invalid signature for com.ATTO.driver.ATTOThunderLinkSASHBA, will not load

What do I need to do to safely load the kernel extension so that my LTO tape drive will work again?

  • We're trouble shooting that right now. My boss is the terminal guru. He says he's trying to put it in "kext dev mode 1" whatever that means. I'm using a thunderlink and it's broken with Sierra, too. Irks me that they announced support for sierra in september. Have you had any luck yet? globenewswire.com/news-release/2016/09/20/873288/10165225/en/… Commented Nov 1, 2016 at 13:32
  • @JasonConrad Edited to add that the specific hardware is an ATTO Thunderlink SH 1068.
    – user260467
    Commented Nov 1, 2016 at 17:14

3 Answers 3


I think I've got this to to work. Further to Jason Conrad's answer above, ATTO seem to have rolled the SH 1068 driver into the SH 2068 package.

Now, why they don't make this clear to anyone without actually downloading the driver and attempting to install, I don't know.

What I do know is that after installing the driver for the SH 2068 (that is signed, so works on Sierra) I can now see my LTO tape library.

Grab the installers from here: https://www.atto.com/downloads/165/


you can turn off System Integrity Check in Sierra by following the instructions on this page: http://osxdaily.com/2015/10/05/disable-rootless-system-integrity-protection-mac-os-x/

Also try and get a newer version of the drivers from Atto's website. For example the Thunderlink NT 1101 is discontinued but the driver, version 2.0.7, for the NT2101 says it supports the 1101 and seems to work.

  • For the ATTO Thunderlink SH 1068, there's no newer version for macOS Sierra. While it is possible to disable SIP, the fact that the driver isn't supported would be trouble in the long-term. The options seem to be to migrate the production environment to Windows, Linux, or roll back to El Capitan itself.
    – user260467
    Commented Nov 1, 2016 at 17:16
  • The MacOS Sierra 10.12.5 update re-enabled Rootless, causing the invalid code signature issue to resurface (and the ThunderLink connection to break). Following instructions posted by @JasonConrad fixed this issue again. Commented May 18, 2017 at 17:17

It turns out that it is just not viable to run this outdated kernel extension on Sierra.

My solution was just to retain a dedicated El Capitan system so that I could use this particular hardware.

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