Promise Pegasus not mounting NEW

  • Last Post 04 January 2018
Alberto Guerrero posted this 04 December 2017

Hello there. 

I have the same issue some people are getting here, I have seen no solution so here is my case. 

I've got this "Promise Technology Pegasus3 R6 Mac Edition 24TB 6-Bay Thunderbolt 3 RAID Array (6 x 4TB)". 

I've tried mounting it on a Macbook Pro 2017 15" on it's usb-c ports with no success. 

I have treid downloading every single driver from the support page, even though the firmware is getting me in trouble, becasue it says "Image not recognized" (image attached), so I have not been able to install. 

The Promise Utility works though, but it shows no signal from the Hard drive. 

The button is always red.

This is all the information I have so far! 

I will appreciate your help! Thanks in advance. 

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Venkatachalam Settu posted this 04 December 2017


Have you installed Pegasus 3 driver for Mac? If not, go to below link and download/install it.

Thank you.




Alberto Guerrero posted this 05 December 2017

Hello Venkatachalam, I have installed it and nothing! 

As I was saying, only the firmware is the one that I have not installed. 

Its werid because my usb-c port sees the RAID but not Hard Drive mounting nor the Disk Utility. 


R P posted this 05 December 2017

Hi Alberto,

If you have a new MAC it's probably got High Sierra. High Sierra blocks any third party drivers by default. You need to go to Settings > Security & Privacy > General, and at the bottom of the page you will see a notice that System Software from Promise was blocked. There will be an Allow button, click that and you will have to reboot for the driver to load.


Alberto Guerrero posted this 05 December 2017

Hi Richard! 

Thanks for your help, I did not have any trouble about that! I installed it, reebot... and as the Installation guide says I looked for system information and looked for the extensions and it is in fact, installed. 

Weird, ha? :/ 

R P posted this 05 December 2017

Hi Alberto,

Does the Promise Utility now see the Pegasus?

Is everything OK now or are there still problems?

Alberto Guerrero posted this 05 December 2017


Everything is the same, not working! 

Red button on the power button, Utility is not seeing it still!

Venkatachalam Settu posted this 06 December 2017


As discussed over the chat session, issue has been resolved.

Thank you.

Larry Yaeger posted this 04 January 2018

Where does one install the driver?  The "STOP" sheet about installing the driver says to download the driver and then follow the instructions in the manual, but the manual doesn't mention a driver for Macs, only Windows.  Where/how are you supposed to install the driver?  I have the file, but don't even remember that last time I had to install a Mac driver.

Note: A search for [install mac driver] on the Knowledge Base produces no results.

Edit: Found it. If you unzip the downloaded driver file, it's really nested folders of stuff, including an installation guide as well as the driver itself. It was just a documentation fail.