Pegasus 2 R6 does not mount on macOS Big Sur bêta 11.0

  • Last Post 16 October 2020
Bernard SANCIER posted this 21 September 2020

I have checked the Pegasus with different Mac running previous OS without problem. Mac Mac is an iMac Pro. I am using the converter Thunderbolt 2->3. I have checked all different configuration with previous système and all are ok except on bug sur beta 11

Order By: Standard | Latest | Votes
Tim van Someren posted this 22 September 2020


R P posted this 22 September 2020

Hi Everyone...

For those of you on the beta channel, be advised that betas are intended for testing purposes and the beta experience includes breaking various functionality. No manufacturer supports a beta OS, not even the OS vendor. Betas are the last steps in the test process before a new OS is released.

That being said, this is a known issue and will be resolved as soon as possible after Apple releases the source code for Big Sur.

The workaround is to manually load the driver, there have been no reports of this not working.

The process is below. The first command checks to see if the driver is loaded. The second command loads the driver. The third command verifies that it is loaded.

tests-MacBook-Pro-14:~ test$ kextstat | grep -i stex
tests-MacBook-Pro-14:~ test$ sudo kextload /Library/Extensions/PromiseSTEX.kext/
tests-MacBook-Pro-14:~ test$ kextstat | grep -i stex
  190    0 0xffffff7f83b17000 0xd000     0xd000     com.promise.driver.stex (6.2.13) AE253556-66D8-38D2-B9D1-179B78F29153 <183 13 6 5 3>
tests-MacBook-Pro-14:~ test$

Once loaded it may take 10 or 20 seconds for the drive to appear on the desktop.

One last thing, I do not have Big Sur beta to test with, but Catalina broke a lot of things in that extra permissions have to be granted to run many kinds of software. It's possible that Big Sur has additional permission requirements for drivers to load, checking Settings > Privacy & Security > Privacy for any unchecked premissions for drivers or Promise devices would be a good idea.



Gerald Skrocki posted this 23 September 2020

Reloading the posted driver DOES work. You just need to force quit the installer before it reboots. Restarting the computer repeats the problem.

  • Liked by
  • Bernard SANCIER
Bernard SANCIER posted this 24 September 2020

Merci. çà marche et aide à attendre un correctif

Andy Epprecht posted this 07 October 2020

Same problem here! R4 not recognized after booting into macOS 11 Big Sur beta (20A5384c).

The above workaround with the 'kextload' works but can only be a temporary solution while testing the betas. This should be fixed latest until the official release of Big Sur. 


D. Bruce Yolton posted this 16 October 2020

It look like the issue was resolved in macOS Big Sur Beta 11.0