iMac not shutting down when on UPS power

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Level 1

14 points

iMac not shutting down when on UPS power

I've just put in a new APC Back-UPS ES 550 UPS which the computer has recognized; it's shown in the Energy Saver UPS Shutdown options panel. The UPS status in the menu bar shows there are 12 minutes of capacity left... so that's working.

I've set the option to Shut down the computer after using the UPS battery for: 1 minute.

When I disconnect the UPS power plug, the UPS powers the computer, but it won't shut down .... even after several minutes.

I've tried this several times and changed the shutdown interval to 2 minutes, and it won't shut down.

Any suggestions?

Dick

iMac Flatpanel 22", Mac OS X (10.6.3)

Posted on Sep 5, 2010 9:27 AM

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Answer 1

elmac

Level 5

4,252 points

Sep 5, 2010 11:28 AM in response to Dick Huitema

Hi, have you looked at the FAQ within the manufacturers website? ...L

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Answer 2

Pondini

Level 8

38,863 points

Sep 5, 2010 5:03 PM in response to Dick Huitema

The preferences file may be corrupted.

Try deleting this file (from your top-level Library folder, not your home folder):

/Library/Preferences/SystemConfiguration/com.apple.PowerManagement.plist

Restart your Mac, re-enter the preferences, quit System Preferences, and try again.

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Answer 3

Dick Huitema Author

Level 1

14 points

Sep 6, 2010 1:23 PM in response to elmac

elmac:

Yes. Unfortunately it just shows how to set the parameters, exactly as I have done.

Thanks for asking, though. I have been known to overlook the obvious from time to time!

Dick

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Answer 4

Dick Huitema Author

Level 1

14 points

Sep 6, 2010 2:10 PM in response to Pondini

Pondini:

Thanks for the tip.

Alas, although there were 2 such files and I deleted them both before reentering the settings, this didn't work.

I restarted after moving the files to the trash, as you suggested, so I was surprised to then see the Energy Saver options set the way I had them rather than factory defaults.

I even tried restarting (again) after resetting the preferences slightly to one minute. I unplugged the UPS and waited two minutes.... with no shutdown.

Other thoughts?

Dick

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Answer 5

Pondini

Level 8

38,863 points

Sep 6, 2010 2:19 PM in response to Dick Huitema

Where was the second one?

Quit System Preferences, delete again and +*empty the trash;+* then Restart and see what's there.

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Answer 6

elmac

Level 5

4,252 points

Sep 6, 2010 2:46 PM in response to Dick Huitema

Hi, another thought, not exactly mmmm, instead of unplugging the UPS power cord, Turn Off the circuit breaker to the power socket..maybe unplugging the power cord breaks a circuit within the UPS...L

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Answer 7

captfred

Level 7

26,422 points

Sep 6, 2010 2:56 PM in response to Dick Huitema

Dick,

Based on your post I decided to try my APC XS-1500 to see if it shutdown properly.
Sure enough, I had the same problem you did. System Preferences recognized that a ups was attached because the UPS tab appeared in the Energy Saver preference and the UPS icon on the menu bar was present. However, it wasn't passing the charge information. The current charge state was 100% after running 10 minutes.
The real charge was 85%.

I unplugged the USB feed from the UPS and replugged into a different USB port and problem fixed. The unit then shut down in the proper time period. Note that in the shutdown options, if you have more than one checked, the first one to hit "true" will cause shutdown.

Hope this helps you. Cheers

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Answer 8

Dick Huitema Author

Level 1

14 points

Sep 7, 2010 3:07 PM in response to captfred

captfred:

Thanks for the input!

My USB connection is delivering all the right info, including the % or minutes remaining on the battery.

So that's not it. 😟

Dick

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Answer 9

Dick Huitema Author

Level 1

14 points

Sep 7, 2010 3:15 PM in response to Pondini

Pondini:

Thanks for your prompt and continued help!

The second preference listing was adjacent to the first, if that's what you asked about ("... the second one?".

Emptying the trash and starting over twice didn't help... still running after two minutes with the pref is set to shut down after one. Same story with the other two optional methods (minutes remaining and % of capacity) .

Further thoughts.....?

Dick

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Answer 10

Pondini

Level 8

38,863 points

Sep 7, 2010 3:59 PM in response to Dick Huitema

Dick Huitema wrote:
Pondini:

Thanks for your prompt and continued help!

The second preference listing was adjacent to the first, if that's what you asked about ("... the second one?".

Emptying the trash and starting over twice didn't help... still running after two minutes with the pref is set to shut down after one. Same story with the other two optional methods (minutes remaining and % of capacity) .

That's quite strange. It's a very long shot, but try a different USB port and cable (and combination of the two) anyway.

As I understand it, OSX periodically interrogates the UPS, both to make sure it's still there, and asking for the % of battery power.

When utility power is interrupted, and the UPS switches to battery power, it sends a signal to OSX. I don't think that signal is in response to the request from OSX, so apparently there's either a hardware problem preventing the signal from getting to your Mac, or OSX isn't dealing with it properly.

If different ports/cables don't help, something may be corrupted in your installation of OSX. I'd suggest downloading and installing the "combo" update. That's the cleverly-named combination of all the updates to Snow Leopard since it was first released, so installing it should fix anything that's gone wrong since then, such as with one of the normal "point" updates. Info and download available for 10.6.4 at: http://support.apple.com/kb/DL1048 or, for 10.6.3: http://support.apple.com/kb/DL1017 if that's what you're on. Be sure to do a +Repair Permissions+ via Disk Utility (in your Applications/Utilities folder) afterwards.

But don't delete the download unless it fixes the problem. If it doesn't, reinstall OSX from your Snow Leopard Install disc (that won't disturb anything else). Then re-load the "combo" again.

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Answer 11

Dick Huitema Author

Level 1

14 points

Sep 8, 2010 8:01 AM in response to Pondini

Pandini:

The USB cable and port all are working fine: They transmit frequent updates on battery capacity used, under both AC and battery power, so I don't think there's anything wrong there.

I see I hadn't updated my profile to show that I'm already on OS 10.6.4, which I've been on for some while now.... throughout my UPS troubleshooting.

I suspect the UPS more likely has the flaw. I've contacted APC about it.

Until I get that resolved, do you still think I should go to all the trouble of replacing the OS now?

Thanks for all your good suggestions....

Cheers!!

Dick

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Answer 12

Pondini

Level 8

38,863 points

Sep 8, 2010 8:14 AM in response to Dick Huitema

Dick Huitema wrote:
Pandini:

The USB cable and port all are working fine: They transmit frequent updates on battery capacity used, under both AC and battery power, so I don't think there's anything wrong there.

But is OSX getting the signal that the UPS has switched from utility to battery power? I don't know the details, but it is a separate signal.

It's easy to do, and may work. Give it a shot. At least that will rule it out definitively.

Until I get that resolved, do you still think I should go to all the trouble of replacing the OS now?

Your call. As long as you have good backups (always!), it's very low risk, and there's not much to it, other than a bit of time. And again, it will rule out a possible cause.

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Answer 13

Dick Huitema Author

Level 1

14 points

Sep 8, 2010 2:06 PM in response to Pondini

Pondini:

I think I've tried all your suggestions, and then some, to no avail, so far.... namely:

1. Verified that the USB link is working, by noting that the Energy Save Menu Bar Pulldown list showed the Power Source shifted from "Power Adapter" to UPS when I unplugged the UPS power plug.

2. Downloaded the Combo OSX, installed it and Repaired Disk Permissions on the iMac HD.

3. Checked for other possible fixes, found resetting the System Management Controller (SMC) "may be necessary [if] the computer doesn't respond to the power button when pressed". That sounded close enough to my problem that I did it. (per Article HT3964)

4. Restarted.

5. Set the Display Sleep and Computer Sleep on the Energy Saver UPS preferences to 1 minute in case OSX needs the machine in Sleep mode to shut it down. The Shutdown pref has been set to 1 minute to make testing easy.

6. Verified that Time Machine was not making a backup when I unplugged the UPS. (I thought it might override the shutdown command while it was doing so.)

After taking all these steps, the machine still runs after the UPS plug is out for over two minutes. I checked that both by listening for the fan(?) noise that indicates the computer is running, and pressing a keyboard key to wake it up.

There must be something I've overlooked. Ideas?

Dick

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Answer 14

Pondini

Level 8

38,863 points

Sep 8, 2010 2:15 PM in response to Dick Huitema

Dick Huitema wrote:
. . .
There must be something I've overlooked. Ideas?

I've never seen either of my Macs do that, and haven't seen such a post here, either. All I can think of is something missing/damaged/corrupted in a part of OSX that hasn't changed since 10.6.0.

Reinstall OSX from the Install disc (that won't affect anything else), then apply the "combo" again.

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Answer 15

captfred

Level 7

26,422 points

Sep 8, 2010 2:33 PM in response to Dick Huitema

Dick,

When you unplug the UPS do you get a dialog box on screen that says "Warning! Your computer is now running on UPS backup batter power. Save your documents and shut down soon."

If not, then the system is unaware it's on UPS so the shutdown parameters won't matter.

I know you've verified the the info coming across the USB but have you physically unplugged it and replugged it as Pondini and I suggested?

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