Pegasus32 R4 Fan Running After Computer Shutdown

  • Last Post 22 July 2023
Paul Blake posted this 05 January 2023

I recently queried Pegasus Technical Support why the fan on my new Pegasus 32 R4 kept running after I'd shutdown my computer. They replied that:

"The Pegasus 32 series has a two fan setup, the secondary fan in the Pegasus will continue to run when your MAC is powered off or put to sleep this is by design. In order to have the fan shut off you would need to either power off the Pegasus or disconnect the power cable/thunderbolt to the unit."

The thunderbolt Lacie RAID drives I previously used automatically shutown with the Mac. I am now forced to manually unmount and shutdown the Pegasus drive every time I shutdown my computer; otherise the fan will run for hours or days until I next use the computer again. I then have to manually turn the Pegasus unit back on again when starting up my Mac as it won't power up by itself.

This is a really bad design flaw that hasn't been mentioned in any of the reviews I read. 


The support consultant said:

"This is not an error but the design of the unit, I am not sure if this will be changed in a future firmware update but let me share your feedback to our team."

I hope there is some push to update the firmware.


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Gianluca Cipolat posted this 07 January 2023

For me this is a defect that needs to be adjusted. Because you can't leave a fan on when the appliance is switched off. Promise will have on its conscience thousands of appliances that consume electricity for nothing. Promise must do what is necessary, note that I have 4 x R8 and 1 x R8 32 that this defect manifests itself only for the R8 32!!!!

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Babatunde Akinkuolie posted this 09 January 2023

Older Pegasus models have only one fan and they will go OFF when the unit is put to sleep.


Pegasus 32 models have 2 fans in them. Here is how they work.


1. When the Mac is asleep, and Pegasus is asleep, the big fan rests, and the small fan runs. Pegasus will wake up when Mac wakes up.

2. When the shutdown button or the power button is used, Pegasus powers off, both big and small fan rest. Pegasus will not wake up automatically. It will have to be restarted.

Paul Blake posted this 20 April 2023

Unfortunately there is no answer!!! You have to manually eject and shutdown the drive every time!

I have no idea why Promise would think this is a good design. Why would you want a fan to be running on a device that is off?

Maybe they'll read these forum comments and realise it's a suboptimal design and update the firmware.

I'd certaimly not buy another Pegasus drive again if this "feature'" is retained. 

Mark Atkin posted this 20 July 2023

I've had the same problem with my new Pegasus RAID - two fans and when the computer is shut down the smaller fan stays on.   Why does the fan need to stay on when not in use? This is quite unsatisfactory.  The fan is noisey during use and remains so after shut down.  Annoying and uses power continually.  I've worked out how to shut down the fan by an awkward series of steps beginning with ejecting the drive from the desktop and, at the same time, sitting down he computer by pushing the off button at the back of the mac.  Crazy.  I can't believe this was an intentional design plan. Hoping there's plan to update the firmware to fix this problem and have contacted support but havent heard back. If not I'll be reluctantly buying another brand next time.








Paul Blake posted this 21 July 2023

I do the following sequence when shutting down:

Eject the drive

Turn off the drive by long pressing its on/off button 

Shutdown my Mac

It's not possible to use the on/off button to shut down drive after the Mac is shutdown.

I press the on/off button again to start the drive when restarting my Mac.

I'm still waiting for a firmware fix to correct this major design oversight. Who wants the fan running all the time the computer is not being used??!!!


John Bergin posted this 22 July 2023

Pegasus32 R6 has the same problem. Here's my shutdown sequence:

With the R6 mounted, I shut down my Mac.

The R6 power supply fan continues to run. I have a kill switch for it that I flip to cut power to it. The fan turns off.

The next time I start up my Mac, I make sure the R6 kill switch is not engaged, then I start up my Mac. The R6 powers up automatically and mounts automatically.

If you eject the R6 (or R4) before shutting down your Mac, the automount will not work the next time you start up your Mac.

So, for now, Pegasus32 Mac users have to choose between what they consider the lesser of two evils: 1) Power off the Pegasus32 unit manually after shutdown and preserve the automounting feature, or 2) Eject and manually power off Pegasus32 before shutdown and lose the automounting feature.

Hope this issue gets fixed in a future firmware update.