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Sapote Author

Level 1

47 points

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

57 replies

Jan 19, 2016 4:50 PM in response to DRedfearn

Now that 10.11.3 is out, has anyone tried reconnecting their UPS via USB cable?

I'm on a business trip and haven't had the chance to update my iMac yet.

Jan 19, 2016 8:52 PM in response to DrDuuude!

The Apple KB for 10.11.3 doesn't mention this at all. I have submitted a bug report to Apple, and I will wait and see how they respond.

David

Jan 20, 2016 7:57 AM in response to DrDuuude!

I just plugged in the USB cable from the APC UPS to the Mac - on both my iMacs. I can see the battery icon on the menu at the top of the screen. Both systems now cold boot and restart without problems. I tried both systems several times. So, tentatively, it looks like this issue may have been corrected. There is no response yet to my bug report - but I hope Apple will confirm that this issue has been resolved. The 10.11.3 update documentation doesn't mention this - in fact, the documentation only says:

The OS X El Capitan v10.11.3 Update improves the stability, compatibility, and security of your Mac, and is recommended for all users.

This update:

Fixes an issue that may prevent some Mac computers from waking from sleep when connected to certain 4K displays.

Enterprise content:

Third-party .pkg file receipts stored in /var/db/receipts are now retained when upgrading from OS X Yosemite.

It's too soon to be sure that this is fixed - I will be doing more testing for the next week or so. I suggest others with this problem also try reconnecting and see if the issue has been resolved for them also.

David

Sapote Author

Level 1

47 points

Jan 20, 2016 11:27 AM in response to Sapote

Before this 10.11.3 update mine was doing ok for a while (avoided restart/shutdown), but then started hanging again at start-up at least 5-6 times in a row over the last couple weeks. I would have to do a hard shutdown, unplug APC USB cable, then power on as usual with no problem.

After the update, it hung after the first restart so I thought it was't fixed, but then after another restart and multiple shutdowns OS X started up without any hanging issue, although I have to say the start up time with subsequent "EL Capitan" updates seems a bit slower since the first time I started up my 27" (Late 2015) iMac.

So far so good,... I guess.

Russ R.

Level 4

2,545 points

Jan 22, 2016 3:10 PM in response to Sapote

The 10.11.3 update made no difference whatsoever to my 27' Retina iMac. With that USB cable from the APC UPS connected, (God, I love acronyms) my iMac only made it to the halfway point of the third progress bar. I've zapped and reset everything that I can think of. With 10.11.3, I'm left sitting at the same place.

I'll leave the USB off for now.

Some posters in this thread have said that it works sometimes for them. It never boots up all the way for me. (Then again ... I don't like to sit in front of the computer and constantly force-quit and restart the boot sequence.)

Jan 22, 2016 3:27 PM in response to Russ R.

Sorry to hear that. My two iMacs (an iMac 27 Retina - late 2014) and a 21.5 iMac (mid-2015) both are booting without any problem now. I have tried this many times, and both systems boot without problem every time. It seems there is something else going on for your system.

David

Jan 30, 2016 9:44 AM in response to DRedfearn

My iMac27 Retina is now again failing to boot on a restart or a cold start - I disconnected the UPS USB cable and it failed again - I had to disconnect my two USB3 external drives to get the system to boot. My iMac21.5 is still booting successfully with the UPS USB cable attached. My iMac27 Retina now hangs with a black screen and the mouse cursor visible in the upper left hand corner. (It responds to moving the mouse but clicking does nothing.) It used to fail with the progress bar showing. My bug report to Apple has not been responded to.

Clearly, the "fix" if there was one (we don't know because this is not mentioned in the 10.11.3 update notes) has not really fixed the issue. Very frustrating.

David

Sapote Author

Level 1

47 points

Jan 30, 2016 10:53 AM in response to Sapote

Still no reoccurring hang with mine since last post 10 days ago and I've been purposely restarting/shutting down at least once a day.

Jan 30, 2016 11:28 AM in response to Sapote

How many external USB drives do you have connected? My iMac27 Retina has two WD USB3 drives connected. My iMac21.5 has only one WD USB3 drive connected - and that system seems to boot without problem with the UPS cable connected. I wonder if that makes a difference.

This is clearly related to USB external drives. My WD Thunderbolt drives don't cause any problems at all.

David

Sapote Author

Level 1

47 points

Jan 30, 2016 1:16 PM in response to DRedfearn

1 APC USB CABLE

1-2 USB/LIGHTNING CABLES

That's it now, but I've also had various external HD's connected via USB over the last 2-3 months, mainly because of Thunderbolt interface related issues.

Jan 30, 2016 2:32 PM in response to Sapote

So, beyond the USB cable to the UPS, do you have one or two external USB drives connected? (I too have multiple USB external drives that come on and off the system as I make secondary backups of my data - but they are only connected _after_ the system has booted.

I have a spare WD Thunderbolt Duo drive, and I am moving all my data from one of my USB external drives to that TB drive. My issue is with the external USB drives - not the Thunderbolt drives. That will bring me down to one USB 4TB drive that is being used for Time Machine. Maybe that will make a difference (I'm hoping).

David

Jan 31, 2016 8:50 AM in response to DRedfearn

I disconnected one of my USB3 external drives (I added a TB drive to replace it). Now, the system is back to booting successfully. I wonder if the number of connected USB drives makes a difference? I have a lot of external drives on my system - now three WD Thunderbolt Duo drives (each configured as Raid 1 drives) and one WD USB3 drive being used as the Time Machine backup.

My iMac21.5 (my wife's system) also continues to boot without problem though it also has the USB monitoring cable connected to the APC UPS device. That system only has one USB3 (Time Machine) external drive connected.

What really puzzles me is that after the 10.11.3 update, I tested the iMac27 Retina many times, and it booted without problem with the UPS cable connected. Then suddenly, after ten days, it started failing again - with no further software updates. This is a really weird problem.

David

Sapote Author

Level 1

47 points

Feb 4, 2016 3:44 PM in response to DRedfearn

Only what I said/noted above. This has been the set up for the last few months - since the issue started. OS X has hung at startup with or w/o a USB drive attached, but it's always had the APC Smart-UPS USB cable and Lightning/USB cables/devices (iPhone, iPad,..) attached, plus the Thunderbolt drive in place of USB.

OS X has still been starting up without hanging as mentioned. Who knows why it's been working since update 10.11.3.

Feb 4, 2016 5:36 PM in response to Sapote

My iMac27 is failing to boot again with the UPS cable connected - even with no other USB drives connected. I have the UPS cable disconnected now. Clearly this was not fixed in 10.11.3. My wife's iMac is not having problems with the UPS cable connected. This is so strange. The problem went away for two weeks and then came back consistently every boot. Maybe 10.11.4?

David

Sapote Author

Level 1

47 points

Feb 19, 2016 9:11 AM in response to Sapote

It happened again... but only once. I woke my iMac 27 from sleeping 2-3 days, plugged in my iPad, and it hung at the usual spot after restarting, then started up fine after that following a hard shutdown/power on. The iPad was the only change/addition to USB connections. APC Smart-UPS cable is still plugged in. Very strange. 😕 I've still been performing Restart/Shutdown at least once a day since update 10.11.3 and this has been the only instance of it reverting back to its previous behavior.

APC Back-UPS USB Connection is Causing OS X to Hang at Startup...