Pegasus R4 driver for macOS El Capitan - which one to use please?

  • Last Post 02 August 2022
Erwin Panen posted this 02 August 2022

Hi all,

I would like to use my Promise Pegasus R4 again with an older mac mini that is still running 10.11.6 El Capitan.

I have the R_Promise_Utility_400000009 that I got from a link on this forum, but apparently that will not work with El Capitan.


Could you please point me to the correct driver? Preferably a link.

Thanks a lot for kindly helping out!


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bab akin posted this 02 August 2022

 Below is the Pegasus Series Driver for Mac. The driver is for Mac OS X 10.10 or above for Pegasus1 model

Also ensure that you are using the latest Pegasus series firmware. If not, here is the link below

Below is the link for Pegasus series utility for Mac

Erwin Panen posted this 02 August 2022

Hi bab akin,


Thanks for your reply;

At the moment I'm just testing with some leftover harddrive(s) I have lying around.

I have little to no experience with the Promise Pegasus, so please bear with me.

What I have tried:

- open macOS system information > under Thunderbolt it shows the Pegasus R-Series

- in terminal: when I run promiseutil, it lists a total of 0 HBA(s) and 0 Subsystem(s)

- when I use a browser to connect to the webpam PRO interface, I am greeted with it's login page but I can't log in (I tried the combo administrator password) but then it shows unknown error

- the power button led of the R4 shows orange (which I think indicates something wrong, but what?)


Can you or anyone else advise on how to proceed?

Thanks a lot for helping out!

Erwin Panen posted this 02 August 2022

For what it's worth, the orange colored power led has turned blue.

but it keeps saying "subsytem not found" (when I issue subsys -v)

I have added a screenshot to illustrate what I have:

- webpam PRO

- promiseutil

- promise utility / port setting


Thanks for helping out!

bab akin posted this 02 August 2022

Did you try another thunderbolt cable?

you can try powering off the unit ,remove all drives , power on the empty pegasus chasis and hot plug the drives one by one in each slot

However,I would suggest you to create a websupport ticket for this issue at so that the technical support team can further investigate this issue and assist you further.