Pegasus 32 will not mount after upgrading to MacOS 26.2 for M1 iMac

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  • Last Post 23 December 2025
Eric Marchisin posted this 21 December 2025

I had MacOS 26 and 26.1 and the Pegasus32 was working perfectly. I just upgraded two nights to 26.2 and now the Pegasus will not mount. 

I ran the terminal command - systemextensionsctl list | grep promise and get driver 21.1.0 and says its activated and waiting for user. 

I checked system information and I can see Pegasus32 under Thunderbolt USB bus 0 and says device is connected. I go to disc utility and nothing. I wanted to downgrade back to 26.1 but guess what, all my backups are on the promise array so I can only see the last 24 hours which is all 26.2. Please help as not only do I not have backups but I also have over 4 terabytes of videos and pictures that I cannot access. 

I have restarted 3 times. I have manually shut down and unplugged unit and waited a few minutes and then restarted, still nothing. I have plugged and unplugged the thunderbolt cable, which from above I know is working since it can be found. Also based on your download page I know I have latest version of Promise Pro Utility and would assume I have latest version of drivers installed as I have a M1 iMac as I stated, it was working with 26.0 and 26.1. But I have not tried to uninstall or reinstall drivers yet. 

Please help?!?

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R P posted this 22 December 2025

Hi Eric,

> I ran the terminal command - systemextensionsctl list | grep promise and get driver 21.1.0 and says its activated and waiting for user.

This is the problem right here, you will need to give the driver permission to run.

The driver dmg file contains 2 PDF files that show how this is done. Tahoe is the same as Sequoia with reagards to driver installation.

This KB also shows you how.

Skip to the seection where you see an OPEN SYSTEM SETTINGs button boxed in red, the steps after that show how to give the driver premission to run.

Eric Marchisin posted this 22 December 2025

Ok I followed the instructions when I tried to install the driver the first time it said the install was blocked. I went to security/privacy but nothing was showing by the all apps and known installers section like I have seen before. So i tried another install but this time it installed successfully. But when I run the command in the terminal, it still says waiting on user. But your screen shots no longer align so I have no idea on how to activate the driver.  I went to login & extensions screen and I can see Promise Technology Mobile Apps which is activated but there is no info button or box for me to click on like the instructions show for Sequoia so how do you activate the driver. There is no extensions or driver extensions as the screens show, so login & extensions is the only thing I can think of. 

I even attempted to uninstall promise utility pro and the driver but Mac OS 26 won't let you uninstall the driver. I put the driver app in the trash but the kext file still remained in system/library/extensions so it was really never removed. I tried booting into safe mode and even running csrutil disable to remove the SIP settings but nothing worked. So after rebooting 6 times by time I re-enabled SIP protection, i reinstalled the driver and utilty pro but no difference. 

Please Help!!!!

R P posted this 22 December 2025

Hi Eric,

Please email support@promise.com and mention the problem and make sure to include a contact number.

R P posted this 23 December 2025

Status Update:

The issue is fixed, in Tahoe Apple added vertical tabs and the system extention button is in the non-selected tab.

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