Possible to install macOS Catalina on Pegasus2 M4?

  • Last Post 08 December 2019
Hank Lin posted this 05 December 2019

Hello folks.  I was asked by someone to install macOS Catalina on a volume in a Pegasus2 M4. I have the M4 connected via Thunderbolt to a late 2013 15" MacBook Pro, which is running macOS High Sierra (10.14.6).

I am able to use Disk Utility to wipe one of the 4TB disks, and created a 4TB APFS container.  I have the current 10.15.1 macOS Catalina installer (from the App Store), which I opened and pointed to the aforementioned 4TB APFS volume.  The installer runs for a few minutes, then reboots as expected. 

This is there things stop behaving.  I expect the Mac to reboot, and resuming installing Catalina, but that is not what happens.  The Mac simply boots back up from it's internal SSD, and back into macOS High Sierra.  When the M4 voumes mount, I can see the target Catalina volume has a folder written called "macOS Install Data".

Anyone have any idea why I am not able to install macOS Catalina onto this Pegasus2 M4?  I tried the installation by running the macOS installer from the internal SSD, as well as creating a USB macOS install disk.  Both methods seem to fail at the same point, after the first reboot of the macOS installer.

Ranjith kumar posted this 08 December 2019

Hi Hank,

-Kindly let us know why you are looking for installing the Mac Catalina OS at Pegasus2 M4.

If you are looking for Mac OS update from 10.14.6 (High Sierra to 10.15(Catalina), then go to

Apple icon-System preference-Software update.

Note:Pegasus2 does not support any file format, it can be use as raw storage.

Please reach us through support.promise.com for quick response.

Thank you,



Promise Team