Why does time machine stop working when my iMac sleeps?

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Level 1

14 points

Why does time machine stop working when my iMac sleeps?

Just recently every time I leave the iMac for a while and it goes to sleep, upon awaking there is a string of messages that the external Seagate 2T backup disk was not ejected properly when shut off. Also I check and see that time machine has not backed up since it went to sleep, often for twelve hours or so. There is not a time shown on the messages, but looks like one is generated every hour.

When I waken the iMac and open the time machine icon at the upper right corner, I see the last backup was prior to it going to sleep and it starts a new backup which completes.

I ran disk utility on the external drive and it found no problems.

I've updated ElCapitan each time a new update was available. Now running 10.11.3.

Can't find anything like this in any of the forums.

Any suggestions??

iMac with Retina 5K display, OS X El Capitan (10.11.2), 8 GB, Late 2014, Airport Extreme,

Posted on Feb 5, 2016 10:21 PM

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Answer 1

chroot

Level 4

1,102 points

Feb 5, 2016 11:09 PM in response to veehb

Sleep mode is designed to stop everything, Time Machine is not suppose to be able to backup while in sleep mode. If you want Time Machine to backup while in sleep mode then try using Power Nap if available.

How Power Nap works on your Mac - Apple Support

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Answer 2

veehb Author

Level 1

14 points

Feb 6, 2016 8:49 PM in response to chroot

Thanks for the reply, chroot.

I have it set to Power Nap and also to not stop the disk drives when asleep.

But, prior the the past week, it would do a time machine backup while asleep. It would do one every hour.

When this problem arose, there were no backups while asleep and about every hour a message that the external drive was not ejected. I suspect it got the message every time it tried to do a time machine backup (hourly).

The actual message says:

Disk Not Ejected Properly

Eject "SEAGATE 2TB" before

disconnecting or turning it off"

The external drive is plugged into the USB 3 connector on the back of the iMac, as it has been since I got it last year. I'm going to eject it and then move it to a powered USB extender and see if that makes any difference.

This is concerning as I don't want to lose my back ups. Maybe time to do an independent one on another external drive.

Has anyone else seen this??

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Answer 3

veehb Author

Level 1

14 points

Feb 10, 2016 3:39 PM in response to veehb

Guess no one is looking at this topic.

Some updates: I was wrong. It doesn't do a time machine update while it is asleep.

I moved the external HD from the USB connection on the back of the iMac to another one. Didn't make much difference. If I'm on the computer for a while the time machine does back up the Macintosh HD every hour and the backups look good.

Disk Utility didn't find a problem with the external disk. This only started happening about the time the last update to ElCapital was installed (10.11.3). But, if it were a problem with the update others would be posting about it. So far I don't see any others with this problem. The Seagate 2TB external drive has it's own power supply, so it shouldn't be trying to take power from the iMac USB.

I tried setting the Energy Saver System Preference to "Enable Power Nap" and it did do backups while asleep, but then I work the computer, I had to log back in as a user. I still saw a few of these messages in that mode. The only box checked right now is Wake for Network Access. Not sure that is necessary, but it is the default setting.

Do I have to eject the external drive every time I leave the iMac? That would probably solve the problem. But then I think I'd have to unplug it from the USB and then replug it for it to be seen again when I awaken the iMac from sleep. I hate to do that. Maybe I could cycle the power supply on the external drive so the iMac could remount it?

I've looked at the logs, but can't see anything that jumps out and I don't know how to read them any way. I'd be pleased to take a screen shot of a log, if it would help identify what is happening here. May not be a serious problem. But in my five years experience with the Apple world on a MBP 15" early 2011 and on this iMac 27" 5K I have not seen this problem until the past few weeks.

Hoping someone with more experience can give me a suggestion. Am I fighting with windmills here?

Thanks,

Veehb

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