Can MacOS shutdown safely if connected to a UPS?

We have several power losses each year. I need to get UPS’s for my Macmini and for my Synology.

Can MacOS take advantage of being connected to a UPS, and do a graceful shutdown before the battery level drops to an unsafe level?

Google (or your favorite search engine) “macos ups” to find good articles, including Apple’s Set when your Mac shuts down when using a UPS - Apple Support.

Or skip that and go direct on your Mac the Apple Icon → System Preferences → Energy Saver and see the tab “UPS”.

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Mine isn’t set up now, but my Mac used to be connected to my APC UPS that has a USB cable to connect it to the Mac. As far as I am aware, it’s that connection you are looking for in a UPS. Then it works a charm.


My CyberPower powers my Synology NAS, router, cable modem, and iMac Pro. Since the iMac Pro is a space heater in disguise (and the reason my office is a couple of degrees warmer than the rest of the house), run time for all this is maybe five minutes. Anyway…

Two for one

The UPS is connected to the NAS by USB, and the NAS sends an email when it goes onto backup power. Since one can run an AppleScript in Mail on receipt of a certain email, my intention is to use that as a trigger to shutdown the iMac. Haven’t gotten around to that last part yet, and the few power failures we have result in “jerking the plug” on the iMac. So far, it’s been robust to these failures with no data loss.


No need for all this complexity. Synology uses the nut UPS software. If you install that on the other devices, including the iMac, you can take advantage of the networking capabilities of nut. Just add the IP-addresses of the other devices to the UPS panel in DSM.

I’m using it myself for several computers, although not for a Mac.

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Something was nagging me in the back of my mind that I had looked into something else. I think this was it, but I never set it up.

Simple answer is, yes. Pre-requisite is vendor software. And good software is a very good reason to pay a bit more and get a reputable brand with good software.

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Simple answer is no. :wink: Well, not completely that is. The Network UPS Tools (nut for short) are open source and support all major brands. Reliably. That’s the software that’s used by Synology (although they don’t use the name) and can be use on many Linux-based systems.
On other machines I use APC software (Linux version too) which is supported by the vendor, and works equally well.

With an UPS the combination of hard- and software is what’s important. The software doesn’t necessarily need to be provided by the vendor though.

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Is there a simple setup guide for NUT on macOS?
I’ve read the manual which is bewildering and it doesn’t even mention where the config files are located.
I installed NUT through homebrew, which may further complicate things.

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I only see that tab after I have a UPS set up with the cable to the Mac.

The last time I installed UPS software from APC it really was designed for servers and racks of UPSs and Servers.

For 1 ups and 1 Mac and maybe a bit of network equipment I would use the OS built in software in the control panel and steer well clear of the official software.

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My preference is to have one UPS per machine. This allows for longer runtime. I’ve bought both Cyberpower and APC.

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Sorry, I can’t help you with that. I’m only using nut on Linux servers (and a Synology).

I found some old(er) guides on the net (one is talking about Sierra) and it also seems they use the package from fink, not homebrew. However, this guide does have all the settings you need it seems.

In any case, going the NUT route seems to be far more reliable (and thus worth the investigation) than using mail. Sending mail takes time and you can’t depend on the moment it arrives.