Q: APC Back-UPS USB Connection is Causing OS X to Hang at Startup...
I just received the Back-UPS yesterday and plugged my iMac 27 into it last night. After that I connected the USB cable between them to bring up the System Preferences>Energy Saver>UPS settings tab/window and then set >Shutdown Options: "Shut down the computer when the UPS battery level is below: 25%. That's it. Everything seemed fine until I tried starting up my iMac after being shut down. It hangs at the startup screen (black background, Apple logo w/ progress bar). The progress bar gets to the middle and stops. Nothing happens beyond that. It's frozen. I have to do a hard manual shutdown by holding down the power button for 5+ secs. I realized it must be the UPS USB connection since that was the only change/addition made to the iMac. And sure enough, once the USB cable was removed from iMac it started right up. I tried it another time to confirm and got the same result - hang at startup screen.
So what's causing this; OS X, APC UPS, or both? It's obviosuly not the APC SW since it's not installed (OS X not supported - and why is that after all these years?). Why would OS X hang at startup from seeing APC UPS US connection? If this can't be resolved right away, I'll have to return it. The whole point of having this UPS is to protect and be able to safely shut down the iMac (either manually or automatically). And don't say; "Unplug it, then plug in after start up".
APC Back-UPS BE550G
iMac (Retina 5K, 27-inch, Late 2015), OS X El Capitan (10.11.1), 24 GB Memory
Posted on Nov 4, 2015 6:03 PM
POSSIBLE SOLUTION!
When in doubt... turn off/disconnect everything. It's been working for me so far after multiple Restarts/Shut Downs.
Here's what I did:
- Shut Down Mac and unplug from APC UPS.
- Power Off APC UPS and unplug from wall outlet.
- Disconnect USB cable.
- Not that it probably matters at this point, but that's what I did.
- Also, keep in mind that I had set up UPS Prefs and also performed the above "Before Resetting/Resetting SMC" instructions, but the latter did not help.
- Wait 15-30 secs.
- Connect USB cable between Mac and APC UPS.
- Plug in APC UPS.
- I can't recall if I turned on power here or after next step - sorry.
- Plug in Mac to APC UPS.
- Power On APC UPS.
- Power On Mac.
Hopefully it'll startup like normal now and bring up the login screen.
Posted on Nov 6, 2015 5:50 PM


